ediff-meta-buffer-verbose-message is a variable defined in `ediff-mult.el'.
Its value is

"Ediff Session Group Panel: %s\n\nUseful commands (type ? to hide them and free up screen):\n button2, v, or RET over session record: start that Ediff session\n M: in sessions invoked from here, brings back this group panel\n R: display the registry of active Ediff sessions\n h: mark session for hiding (toggle)\n x: hide marked sessions; with prefix arg: unhide\n m: mark session for a non-hiding operation (toggle)\n uh/um: unmark all sessions marked for hiding/operation\n n,SPC: next session\n p,DEL: previous session\n E: browse Ediff manual\n T: toggle truncation of long file names\n q: quit this session group\n"

  • This variable may be risky if used as a file-local variable.

Not documented as a variable.