diff --git a/readme.md b/readme.md
index 1a0197f..559e788 100644
--- a/readme.md
+++ b/readme.md
@@ -211,13 +211,10 @@ Handle project workflows in a unified way:
 
 ## When
 
-### Tasks for a 1st stable release
-
-#### Shell
+### Shell
 
 * comment
 * drawing characters constants
-* handle errors
 * packages
   * configure
     * apk
@@ -228,8 +225,9 @@ Handle project workflows in a unified way:
       * codecs repository
       * disable & enable https
 * test
+* underscore internals
 
-#### Shell → Python
+### Shell → Python
 
 * check file & variable sums
 * install system packages
@@ -249,7 +247,7 @@ Handle project workflows in a unified way:
     * activate
 * relay environment module name
 
-#### Python
+### Python
 
 * check
   * .py
@@ -266,7 +264,7 @@ Handle project workflows in a unified way:
 * try git repo url variable first for shunit
 * test
 
-### Task stack
+### Later
 
 * automate versions fetching
 * document behavior differences
diff --git a/spcd/bootstrap.sh b/spcd/bootstrap.sh
index 26aed02..5d56ad3 100644
--- a/spcd/bootstrap.sh
+++ b/spcd/bootstrap.sh
@@ -36,9 +36,9 @@
 [ -n "${SPCD_URL_UBUNTU}" ] ||
     SPCD_URL_UBUNTU="https://ubuntu.mirrors.ovh.net/ubuntu"
 
-# ╭───╮
-# │ _ │
-# ╰───╯
+# ╭───────────╮
+# │ internals │
+# ╰───────────╯
 
 _spcd_fill() {
     _spcd_fill__index=${1}
@@ -49,9 +49,9 @@ _spcd_fill() {
     unset _spcd_fill__index
 }
 
-# ╭───┬────────╮
-# │ _ │ banner │
-# ╰───┴────────╯
+# ╭───────────┬────────╮
+# │ internals │ banner │
+# ╰───────────┴────────╯
 
 _SPCD_BANNER_DOWN_AND_HORIZONTAL="┬"
 _SPCD_BANNER_DOWN_AND_LEFT="╮"
@@ -156,16 +156,16 @@ _spcd_banner_wipe() {
         __SPCD_BANNER_BOTTOM
 }
 
-# ╭───┬───────╮
-# │ _ │ error │
-# ╰───┴───────╯
+# ╭───────────┬───────╮
+# │ internals │ error │
+# ╰───────────┴───────╯
 
 _SPCD_ERROR_CI=1
 _SPCD_ERROR_OS=2
 
-# ╭───┬───────╮
-# │ _ │ frame │
-# ╰───┴───────╯
+# ╭───────────┬───────╮
+# │ internals │ frame │
+# ╰───────────┴───────╯
 
 _SPCD_FRAME_TOP="╭╴"
 _SPCD_FRAME_BOTTOM="╰╴"
@@ -178,9 +178,9 @@ _spcd_frame_shut() {
     echo "${_SPCD_FRAME_BOTTOM}${1}"
 }
 
-# ╭───┬────╮
-# │ _ │ os │
-# ╰───┴────╯
+# ╭───────────┬────╮
+# │ internals │ os │
+# ╰───────────┴────╯
 
 _spcd_os_cat() {
     if [ -n "${1}" ]; then
@@ -190,17 +190,17 @@ _spcd_os_cat() {
     fi
 }
 
-# ╭───┬──────╮
-# │ _ │ rule │
-# ╰───┴──────╯
+# ╭───────────┬──────╮
+# │ internals │ rule │
+# ╰───────────┴──────╯
 
 _SPCD_RULE_LEFT="╶"
 _SPCD_RULE_MIDDLE="─"
 _SPCD_RULE_RIGHT="╴"
 
-# ╭───┬──────╮
-# │ _ │ step │
-# ╰───┴──────╯
+# ╭───────────┬──────╮
+# │ internals │ step │
+# ╰───────────┴──────╯
 
 _spcd_step_wipe() {
     unset \
@@ -227,6 +227,30 @@ spcd_error_os() {
     exit "${_SPCD_ERROR_OS}"
 }
 
+# ╭───────────┬─────╮
+# │ functions │ git │
+# ╰───────────┴─────╯
+
+spcd_git_clone() {
+    if [ -n "${1}" ]; then
+        spcd_gc__name="$(basename "${1}")"
+        spcd_gc__path="${SPCD_DL}/${spcd_gc__name}"
+        spcd_gc__url="$(spcd_git_url "${1}")"
+        git clone "${spcd_gc__url}" "${spcd_gc__path}"
+        echo "${spcd_gc__path}"
+    fi
+}
+
+spcd_git_url() {
+    if [ -n "${1}" ]; then
+        case "${1}" in
+        http*) echo "${1}" ;;
+        */*) echo "${SPCD_PROJECT_ROOT}/${1}" ;;
+        *) echo "${SPCD_PROJECT_ROOT}/${SPCD_PROJECT_PATH}/${1}" ;;
+        esac
+    fi
+}
+
 # ╭───────────┬─────────╮
 # │ functions │ openssl │
 # ╰───────────┴─────────╯
@@ -339,13 +363,13 @@ spcd_step_out() {
     __SPCD_STEP_LEVEL=$((__SPCD_STEP_LEVEL - 1))
 }
 
-# ╭──────╮
-# │ step │
-# ╰──────╯
+# ╭───────╮
+# │ steps │
+# ╰───────╯
 
-# ╭──────┬───────────╮
-# │ step │ constants │
-# ╰──────┴───────────╯
+# ╭───────┬───────────╮
+# │ steps │ constants │
+# ╰───────┴───────────╯
 
 SPCD_OS_ALMA="alma"
 SPCD_OS_ALPINE="alpine"
@@ -362,11 +386,11 @@ SPCD_PM_DNF="dnf"
 SPCD_PM_PACMAN="pacman"
 SPCD_PM_ZYPPER="zypper"
 
-# ╭──────┬─────────────╮
-# │ step │ environment │
-# ╰──────┴─────────────╯
+# ╭───────┬─────────────╮
+# │ steps │ environment │
+# ╰───────┴─────────────╯
 
-spcd_step__environment_set_variables() {
+spcd_environment_set_variables() {
     spcd_step "Set variables"
     # check script first
     [ -n "${SPCD}" ] || spcd_error_ci "SPCD"
@@ -555,6 +579,41 @@ ${SPCD_PROJECT_ROOT}$(basename "${GITHUB_SERVER_URL}")"
     esac
     spcd_split
     spcd_os_printenv "SPCD_PM"
+    # set package manager variables
+    case "${SPCD_PM}" in
+    "${SPCD_PM_DNF}")
+        SPCD_PM_HTTPS_PATH="/etc/dnf/dnf.conf.d/https.conf"
+        SPCD_PM_HTTPS_TEXT="\
+sslverify=False
+"
+        ;;
+    "${SPCD_PM_APK}")
+        SPCD_PM_HTTPS_PATH="/etc/apk/repositories.d/https"
+        SPCD_PM_HTTPS_TEXT="\
+--no-verify
+"
+        ;;
+    "${SPCD_PM_PACMAN}")
+        SPCD_PM_HTTPS_PATH="/etc/pacman.d/https.conf"
+        SPCD_PM_HTTPS_TEXT="\
+SSLVerify = No
+"
+        ;;
+    "${SPCD_PM_APT}")
+        SPCD_PM_HTTPS_PATH="/etc/apt/apt.conf.d/https"
+        SPCD_PM_HTTPS_TEXT="\
+Acquire::https::Verify-Peer False;
+"
+        ;;
+    "${SPCD_PM_ZYPPER}")
+        SPCD_PM_HTTPS_PATH=""
+        SPCD_PM_HTTPS_TEXT="\
+"
+        ;;
+    *) ;;
+    esac
+    spcd_split
+    spcd_os_printenv "SPCD_PM_HTTPS_PATH"
     # specific
     case "${SPCD_OS_ID}" in
     "${SPCD_OS_ALMA}")
@@ -705,15 +764,15 @@ ${SPCD_PYTHON_VENV}/lib/${SPCD_PYTHON_COMMAND}/site-packages"
     spcd_os_printenv "SPCD_DL"
 }
 
-spcd_step__environment_list_workspace() {
+spcd_environment_list_workspace() {
     spcd_step "List workspace"
     spcd_lwd__path="$(realpath .)"
     spcd_os_ls "${spcd_lwd__path}"
 }
 
-# ╭──────┬───────────╮
-# │ step │ functions │
-# ╰──────┴───────────╯
+# ╭───────┬───────────╮
+# │ steps │ functions │
+# ╰───────┴───────────╯
 
 spcd_clean_cache() {
     case "${SPCD_PM}" in
@@ -726,37 +785,6 @@ spcd_clean_cache() {
     esac
 }
 
-spcd_git_clone() {
-    if [ -n "${1}" ]; then
-        spcd_gc__name="$(basename "${1}")"
-        spcd_gc__path="${SPCD_DL}/${spcd_gc__name}"
-        spcd_gc__url="$(spcd_git_url "${1}")"
-        git clone "${spcd_gc__url}" "${spcd_gc__path}"
-        echo "${spcd_gc__path}"
-    fi
-}
-
-spcd_git_url() {
-    if [ -n "${1}" ]; then
-        case "${1}" in
-        http*) echo "${1}" ;;
-        */*) echo "${SPCD_PROJECT_ROOT}/${1}" ;;
-        *) echo "${SPCD_PROJECT_ROOT}/${SPCD_PROJECT_PATH}/${1}" ;;
-        esac
-    fi
-}
-
-spcd_https_path() {
-    case "${SPCD_PM}" in
-    "${SPCD_PM_APK}") echo "/etc/apk/repositories.d/https" ;;
-    "${SPCD_PM_APT}") echo "/etc/apt/apt.conf.d/https" ;;
-    "${SPCD_PM_DNF}") echo "/etc/dnf/dnf.conf.d/https.conf" ;;
-    "${SPCD_PM_PACMAN}") echo "/etc/pacman.d/https.conf" ;;
-    "${SPCD_PM_ZYPPER}") ;;
-    *) ;;
-    esac
-}
-
 spcd_install_package() {
     case "${SPCD_PM}" in
     "${SPCD_PM_APK}") apk add "${1}" ;;
@@ -800,11 +828,11 @@ spcd_query_package() {
     esac
 }
 
-# ╭──────┬─────╮
-# │ step │ dns │
-# ╰──────┴─────╯
+# ╭───────┬─────╮
+# │ steps │ dns │
+# ╰───────┴─────╯
 
-spcd_step__dns() {
+spcd_dns() {
     spcd_step "DNS"
     while true; do
         spcd_sdr__index=$((spcd_sdr__index + 1))
@@ -817,11 +845,11 @@ nameserver ${spcd_sdr__value}
     spcd_os_write "/etc/resolv.conf" "${spcd_sdr__text}"
 }
 
-# ╭──────┬──────────╮
-# │ step │ packages │
-# ╰──────┴──────────╯
+# ╭───────┬──────────╮
+# │ steps │ packages │
+# ╰───────┴──────────╯
 
-spcd_step__packages_set_repositories() {
+spcd_packages_set_repositories() {
     spcd_step "Set repositories"
     case "${SPCD_OS_ID}" in
     "${SPCD_OS_ALMA}")
@@ -888,7 +916,7 @@ deb ${SPCD_URL_CHOSEN} ${SPCD_OS_VERSION}-security main universe
     esac
 }
 
-spcd_step__packages_set_configuration() {
+spcd_packages_set_configuration() {
     spcd_step "Set configuration"
     case "${SPCD_PM}" in
     "${SPCD_PM_DNF}")
@@ -926,35 +954,15 @@ Dir::Etc::SourceParts \"\";
     esac
 }
 
-spcd_step__packages_trust_https() {
+spcd_packages_trust_https() {
     spcd_step "Trust HTTPS"
     if [ -n "${SPCD_CA_1}" ] || [ "${SPCD_PM}" = "${SPCD_PM_APT}" ]; then
-        spcd_pth__path="$(spcd_https_path)"
-        if [ -n "${spcd_pth__path}" ]; then
-            spcd_os_mkdir "$(dirname "${spcd_pth__path}")"
-            case "${SPCD_PM}" in
-            "${SPCD_PM_APK}") spcd_pth__text="\
---no-verify
-" ;;
-            "${SPCD_PM_APT}") spcd_pth__text="\
-Acquire::https::Verify-Peer False;
-" ;;
-            "${SPCD_PM_DNF}") spcd_pth__text="\
-sslverify=False
-" ;;
-            "${SPCD_PM_PACMAN}") spcd_pth__text="\
-SSLVerify = No
-" ;;
-            "${SPCD_PM_ZYPPER}") ;;
-            *) ;;
-            esac
-            [ -n "${spcd_pth__text}" ] &&
-                spcd_os_write "${spcd_pth__path}" "${spcd_pth__text}"
-        fi
+        spcd_os_mkdir "$(dirname "${SPCD_PM_HTTPS_PATH}")"
+        spcd_os_write "${SPCD_PM_HTTPS_PATH}" "${SPCD_PM_HTTPS_TEXT}"
     fi
 }
 
-spcd_step__packages_update_catalog() {
+spcd_packages_update_catalog() {
     spcd_step "Update catalog"
     case "${SPCD_PM}" in
     "${SPCD_PM_APK}") apk update ;;
@@ -966,7 +974,7 @@ spcd_step__packages_update_catalog() {
     esac
 }
 
-spcd_step__packages_install_tools() {
+spcd_packages_install_tools() {
     spcd_step "Install tools"
     case "${SPCD_PM}" in
     "${SPCD_PM_APT}") spcd_install_package "apt-utils" ;;
@@ -974,16 +982,16 @@ spcd_step__packages_install_tools() {
     esac
 }
 
-# ╭──────┬────╮
-# │ step │ ca │
-# ╰──────┴────╯
+# ╭───────┬────╮
+# │ steps │ ca │
+# ╰───────┴────╯
 
-spcd_step__ca_install_package() {
+spcd_ca_install_package() {
     spcd_step "Install package"
     spcd_install_package "ca-certificates"
 }
 
-spcd_step__ca_write_certificates() {
+spcd_ca_write_certificates() {
     spcd_step "Write certificates"
     case "${SPCD_OS_ID}" in
     "${SPCD_OS_ALMA}" | "${SPCD_OS_FEDORA}" | "${SPCD_OS_ROCKY}")
@@ -1012,7 +1020,7 @@ spcd_step__ca_write_certificates() {
     done
 }
 
-spcd_step__ca_update_certificates() {
+spcd_ca_update_certificates() {
     spcd_step "Update certificates"
     case "${SPCD_OS_ID}" in
     "${SPCD_OS_ARCH}" | \
@@ -1031,17 +1039,16 @@ spcd_step__ca_update_certificates() {
     esac
 }
 
-# ╭──────┬──────────╮
-# │ step │ packages │
-# ╰──────┴──────────╯
+# ╭───────┬──────────╮
+# │ steps │ packages │
+# ╰───────┴──────────╯
 
-spcd_step__packages_verify_https() {
+spcd_packages_verify_https() {
     spcd_step "Verify HTTPS"
-    spcd_pvh__path="$(spcd_https_path)"
-    [ -n "${spcd_pvh__path}" ] && spcd_os_rm "${spcd_pvh__path}"
+    spcd_os_rm "${SPCD_PM_HTTPS_PATH}"
 }
 
-spcd_step__packages_upgrade_system() {
+spcd_packages_upgrade_system() {
     spcd_step "Upgrade system"
     case "${SPCD_PM}" in
     "${SPCD_PM_APK}") apk upgrade ;;
@@ -1053,21 +1060,21 @@ spcd_step__packages_upgrade_system() {
     esac
 }
 
-spcd_step__packages_install_dos2unix() {
+spcd_packages_install_dos2unix() {
     spcd_step "Install dos2unix"
     spcd_install_package "dos2unix"
 }
 
-spcd_step__packages_install_git() {
+spcd_packages_install_git() {
     spcd_step "Install Git"
     spcd_install_package "git"
 }
 
-# ╭──────┬────────╮
-# │ step │ python │
-# ╰──────┴────────╯
+# ╭───────┬────────╮
+# │ steps │ python │
+# ╰───────┴────────╯
 
-spcd_step__python_install() {
+spcd_python_install() {
     spcd_step "Install package"
     spcd_install_package "${SPCD_PYTHON_PACKAGE}"
     spcd_step "Link alias to command"
@@ -1094,7 +1101,7 @@ index-url = ${SPCD_URL_PYTHON}
     spcd_step_out
 }
 
-spcd_step__python_modules() {
+spcd_python_modules() {
     spcd_step_in "Modules"
     spcd_ipm__target="${SPCD_PYTHON_VENV_PACKAGES}"
     spcd_step "List"
@@ -1119,7 +1126,7 @@ spcd_step__python_modules() {
     spcd_step_out
 }
 
-spcd_step__install_packages() {
+spcd_install_packages() {
     spcd_step_in "OS packages"
     # epel
     spcd_step "EPEL"
@@ -1179,7 +1186,7 @@ spcd_step__install_packages() {
     spcd_step_out
 }
 
-spcd_step__python_write_module() {
+spcd_python_write_module() {
     spcd_step "Write module"
     for spcd_wpm__variable in \
         OS_ID OS_VERSION \
@@ -1199,7 +1206,7 @@ SPCD_STEP = ${spcd_wpm__index}
     done
 }
 
-spcd_step__python_switch() {
+spcd_python_switch() {
     spcd_step "Switch"
     spcd_stp__name="$(basename "${SPCD_GIT_MAIN}")"
     spcd_stp__path="$(realpath "${0}")"
@@ -1217,40 +1224,40 @@ ${SPCD_PYTHON_ALIAS} / ${spcd_stp__name}"
 spcd_main() {
     # environment
     spcd_step_in "Environment"
-    spcd_step__environment_set_variables
-    spcd_step__environment_list_workspace
+    spcd_environment_set_variables
+    spcd_environment_list_workspace
     spcd_step_out
     # dns
-    spcd_step__dns
+    spcd_dns
     # packages
     spcd_step_in "Packages"
-    spcd_step__packages_set_repositories
-    spcd_step__packages_set_configuration
-    spcd_step__packages_trust_https
-    spcd_step__packages_update_catalog
-    spcd_step__packages_install_tools
+    spcd_packages_set_repositories
+    spcd_packages_set_configuration
+    spcd_packages_trust_https
+    spcd_packages_update_catalog
+    spcd_packages_install_tools
     spcd_step_out
     # ca
     spcd_step_in "CA"
-    spcd_step__ca_install_package
-    spcd_step__ca_write_certificates
-    spcd_step__ca_update_certificates
+    spcd_ca_install_package
+    spcd_ca_write_certificates
+    spcd_ca_update_certificates
     spcd_step_out
     # packages
     spcd_step_in "Packages"
-    spcd_step__packages_verify_https
-    spcd_step__packages_update_catalog
-    spcd_step__packages_upgrade_system
-    spcd_step__packages_install_dos2unix
-    spcd_step__packages_install_git
+    spcd_packages_verify_https
+    spcd_packages_update_catalog
+    spcd_packages_upgrade_system
+    spcd_packages_install_dos2unix
+    spcd_packages_install_git
     spcd_step_out
     # python
     spcd_step_in "Python"
-    spcd_step__python_install
-    spcd_step__python_modules
-    spcd_step__install_packages
-    spcd_step__python_write_module
-    spcd_step__python_switch
+    spcd_python_install
+    spcd_python_modules
+    spcd_install_packages
+    spcd_python_write_module
+    spcd_python_switch
 }
 
 spcd_main