License

[tansiret]

Are there any specific reason that a permissive license like MIT is used? Can a copyleft license like LGPL for the framework, which lets its usage at proprietary projects but prevents the framework's source code being stolen?

You can take a look about the comparison of copyleft and permissive here: https://opensource.stackexchange.com/questions/21/whats-the-difference-between-permissive-and-copyleft-licenses

Difference of LGPL and GPL, and why LGPL is suitable for libraries and won't cause you a problem at all about compatibility with commercial stuff while protecting your source code with copyleft: https://www.difference.wiki/gpl-vs-lgpl/