As far as I know, if you customize canvas, you have to release the source code according to AGPLv3.
If I make an external app (LTI),
1. Do I have to release all of my app's source code?
2. If I were to release it, how far should I open it?
3. Is there an official document or column related to the above? (IMPORTANT)
Please let me know if there is a link related to the license or copyright regarding the lti development.