the tutorial says to use tuareg mode for mlg files: rocq/doc/plugin_tutorial at master · rocq-prover/rocq · GitHub
However, in the same tutorial, when I open rocq/doc/plugin_tutorial/tuto1/src/g_tuto1.mlg at master · rocq-prover/rocq · GitHub, my emacs highlights DECLARE, and make the whole file unreadable.
How did you set things up?

