a really dumb problem that isn't your fault

hi, i have strong-armed my exported annotations for two books, and one worked great. the other failed but had some stray underscores and single or double quotes, i reckon. i'll try again once i fix a somewhat embarrassing situation.

i cannot find where in the heck i can tell my boox (note air 2) that Obsidian can open an `.md` (or anything else either really) and the only other Android device i have is a remote control for one of my drones, so i couldn't possibly be more confused this far from my usual flora and fauna.

i can press and hold and the open-in pops up? but then it says only my boox reader app cam open it regardless of `.md` or `.txt` extensions.

little help? 🙏 never thought i would wish for something like `defaults` or SwiftDefaultApps system preferences pane on macOS!