diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 0f3355bfb..adcdd41f1 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -1,7 +1,8 @@
-# linux CI tests, run on a periodic schedule, on notable pull request
-# to master, and on notable push to ci-linux. Reasonably thorough
-# build/test/benchmark/haddock/functest testing, with all GHC
-# versions. Note periodic runs don't use cache.
+# Thorough linux CI tests: build, test, benchmark, haddock &
+# run functional tests, with all supported GHC versions.
+#
+# Runs: periodically, on notable pull request to master, and on
+# notable push to ci-linux.
 
 name: linux / pull request CI
 
@@ -58,8 +59,7 @@ jobs:
     - name: Check out
       uses: actions/checkout@v2
 
-    # declare/restore cached things
-    # caching doesn't work for scheduled runs yet https://github.com/actions/cache/issues/63
+    # things to be cached/restored:
 
     - name: Cache stack global package db
       id:   stack-global
@@ -81,7 +81,6 @@ jobs:
           ${{ runner.os }}-stack-programs-${{ matrix.plan.key }}
           ${{ runner.os }}-stack-programs
 
-    # stack's local package dbs for the project and each package
     - name: Cache .stack-work
       uses: actions/cache@v2
       with:
@@ -149,7 +148,7 @@ jobs:
         sudo rm -rf "$AGENT_TOOLSDIRECTORY"
         df -h /
 
-    # actions
+    # actions:
 
     - name: Install stack
       # curl -L https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C $INSTALLDIR '*/stack'
diff --git a/.github/workflows/mac.yml b/.github/workflows/mac.yml
index ad8e0cd82..c974b5474 100644
--- a/.github/workflows/mac.yml
+++ b/.github/workflows/mac.yml
@@ -1,5 +1,6 @@
-# mac CI tests, run on a periodic schedule, and on notable push to
-# ci-mac. Note periodic runs don't use cache.
+# Light Mac CI tests: build and run functional tests with one GHC version.
+#
+# Runs: periodically, and on notable push to ci-mac.
 
 name: mac CI
 
@@ -30,8 +31,7 @@ jobs:
     - name: Check out
       uses: actions/checkout@v2
 
-    # declare/restore cached things
-    # caching doesn't work for scheduled runs yet https://github.com/actions/cache/issues/63
+    # things to be cached/restored:
 
     - name: Cache stack global package db
       id:   stack-global
@@ -53,7 +53,6 @@ jobs:
           ${{ runner.os }}-stack-programs
           ${{ runner.os }}-local-bin
 
-    # stack's local package dbs for the project and each package
     - name: Cache .stack-work
       uses: actions/cache@v2
       with:
@@ -84,7 +83,7 @@ jobs:
         path: hledger-web/.stack-work
         key: ${{ runner.os }}-hledger-web-stack-work
 
-    # actions
+    # actions:
 
     - name: Install stack
       # curl --insecure -L https://get.haskellstack.org/stable/osx-x86_64.tar.gz | tar xz --strip-components=1 --include '*/stack' -C $INSTALLDIR
diff --git a/.github/workflows/push.yml b/.github/workflows/push.yml
index ccbb52930..ed73f6476 100644
--- a/.github/workflows/push.yml
+++ b/.github/workflows/push.yml
@@ -1,4 +1,7 @@
-# quick CI tests, run on notable push to master.
+# Light CI tests: build and run functional tests with one GHC version,
+# using less compute power and emitting less carbon.
+#
+# Runs: on notable (eg, not just doc files) push to master.
 
 name: push CI
 
@@ -42,16 +45,14 @@ jobs:
           touch "${filename}" -mt "$(date --date="@$TS" "+%Y%m%d%H%M.%S")"
         done
 
-    # cached things
-
-    # declare/restore cached things
+    # things to be cached/restored:
 
     - name: Cache stack global package db
       id:   stack-global
       uses: actions/cache@v2
       with:
         path: ~/.stack
-        key:          ${{ runner.os }}-stack-global-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-stack-global-${{ hashFiles('**.yaml') }}
         restore-keys: |
           ${{ runner.os }}-stack-global
           ${{ runner.os }}-stack
@@ -61,12 +62,11 @@ jobs:
       uses: actions/cache@v2
       with:
         path: ~/.local/bin
-        key:          ${{ runner.os }}-stack-programs-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-stack-programs-${{ hashFiles('**.yaml') }}
         restore-keys: |
           ${{ runner.os }}-stack-programs
           ${{ runner.os }}-local-bin
 
-    # stack's local package dbs for the project and each package
     - name: Cache .stack-work
       uses: actions/cache@v2
       with:
@@ -102,7 +102,7 @@ jobs:
         key:          ${{ runner.os }}-hledger-web-stack-work-${{ hashFiles('hledger-web/package.yaml') }}
         restore-keys: ${{ runner.os }}-hledger-web-stack-work
 
-    # actions
+    # actions:
 
     - name: Install stack
       # curl -L https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C $INSTALLDIR '*/stack'
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 69c710c3b..28ac93ed4 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -1,6 +1,7 @@
-# windows CI tests, run on a periodic schedule, and on notable push to
-# ci-windows. Note periodic runs don't use cache. Using GHC 8.8.2 for
-# now to avoid https://gitlab.haskell.org/ghc/ghc/issues/17926.
+# Light Mac CI tests: build and run functional tests with one GHC version.
+# GHC 8.8.2 for now to avoid https://gitlab.haskell.org/ghc/ghc/issues/17926.
+#
+# Runs: periodically, and on notable push to ci-windows.
 
 name: windows CI
 
@@ -31,8 +32,7 @@ jobs:
     - name: Check out
       uses: actions/checkout@v2
 
-    # declare/restore cached things
-    # caching doesn't work for scheduled runs yet https://github.com/actions/cache/issues/63
+    # things to be cached/restored:
 
     - name: Cache stack global package db
       id:   stack-global-package-db
@@ -42,11 +42,6 @@ jobs:
         key:          ${{ runner.os }}-appdata-roaming-stack-${{ hashFiles('**.yaml') }}
         restore-keys: ${{ runner.os }}-appdata-roaming-stack
 
-    # - name: showStuff
-    #   shell: bash
-    #   run: |
-    #     ls -lFRa /c/users/runneradmin/appdata/roaming/stack
-
     - name: Cache stack programs dir   # ghc, ghc-included packages and their haddocks, mingw, msys2
       id:   stack-programs-dir
       uses: actions/cache@v2
@@ -57,12 +52,6 @@ jobs:
         key:          ${{ runner.os }}-appdata-local-programs-stack-${{ hashFiles('**.yaml') }}
         restore-keys: ${{ runner.os }}-appdata-local-programs-stack
 
-    # - name: showStuff
-    #   shell: bash
-    #   run: |
-    #     ls -lFRa /c/users/runneradmin/appdata/local/programs/stack
-
-    # stack's local package dbs for the project and each package
     - name: Cache .stack-work
       uses: actions/cache@v2
       with:
@@ -98,7 +87,13 @@ jobs:
         key:          ${{ runner.os }}-hledger-web-stack-work-${{ hashFiles('hledger-web/package.yaml') }}
         restore-keys: ${{ runner.os }}-hledger-web-stack-work
 
-    # actions
+    # - name: showStuff
+    #   shell: bash
+    #   run: |
+    #     ls -lFRa /c/users/runneradmin/appdata/roaming/stack
+    #     ls -lFRa /c/users/runneradmin/appdata/local/programs/stack
+
+    # actions:
 
     # - name: Add stack local bin to PATH
     #   run: echo "::add-path::C:\Users\runneradmin\AppData\Roaming\stack\local\bin"