Hello!
"i wish more devs included the Engine & tools metadata in their projects on itch.io so that, with 1 click, we could find a larger sample of games/apps produced with a given "language" or framework." <-- I agree with you.
"i doubt that i'll ever deviate from my dialect of choice (AppGameKit)" <-- AppGameKit is a good game language. Sure!
"there seems to be a different "flavor" of game produced by various coding communities, in general." <-- Thanks for your analysis.