The Fegg docs are now versioned. Fegg 4.x stays the default; switch versions with the version menu in the navigation bar
Added the Fegg 5.x docs as the version in development (/docs/fegg/next/, English only for now): directory layout and the separated core, base controllers for public pages and the CMS, security (env.php, test server settings, security headers), MySQL, logging and the command line
Fegg 5.x docs (/docs/fegg/next/): every CMS action that changes data must call requirePost() first; this is new in Fegg 5, so CMS controllers copied from Fegg 4 need it added (see the migration guide)
Fegg 5.x docs: which controller methods can be called from a URL, Basic authentication checked before the controller runs, CMS sessions of deleted users, and the first CMS user created only while cms_user is empty