Practice mode · free · unlimited · not certifiable

Versioning and History

Unscored tasks with hints and instant feedback. Practice results never become credentials.

Short lesson

Docs that stay true · 6 min

One source of truth, owners and review dates on every page, link checks in CI, deprecation banners that point to the replacement.

L1Knowledge checkmcq

Which version label is clearest?

L3Restore last Tuesday's policyworkspace

Someone changed the expense policy today by mistake. Restore the version from last Tuesday (2026-10-13) and record why in /policies/CHANGELOG.md (one line with today's date).

L4Git for documentsterminal

The handbook in ~/handbook is a Git repository. Yesterday's commit “Edit leave section” broke the leave rules. Restore handbook.md's leave section by reverting that commit, keeping later commits, and add a CHANGELOG.md entry committed with it.