Hi,
Previously I tried to change the default extension to *.textbundle in the iOS version of fsnotes, then I didn't think it fits my need and I changed it back to *.md.
Somehow no matter what other options I am choosing in the default extension, it is still saving *.textbundle format.
I am using iOS version of fsnotes (2.6) and iOS 12.2.
Thanks
Textbundle is the new default, but is there a setting for that on iOS @glushchenko ?
I think so.

Thank you @jakemkc, fixed. Will be available in AppStore as soon as possible. Container option added.
2.6.1 available in AppStore