It seems their main app is proprietary. See https://lmstudio.ai/app-terms#restrictions-on-use. Example excerpt--though many of the other points in the ToS also makes it very un-FLOSS:

>> You agree that You will not permit any third party to, and You will not itself:[..] (e) reverse engineer, decompile, disassemble, or otherwise attempt to derive the source code for the Software[..]