These 2 command were introduced recently and have no Help page references https://gerrit.libreoffice.org/c/core/+/88586/1 https://gerrit.libreoffice.org/c/core/+/88585/2 and bug#130648
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/help/commit/d883745bda47f21301f6cbf29bbd47512ef9d000 tdf#144339 Add Help page for ProtectFields and ProtectBookmarks