Aseprite

Here is the source code for a non free image editor (it was once GPL):
https://github.com/aseprite/aseprite

yet its license states
https://github.com/aseprite/aseprite/blob/master/EULA.txt

You may not reverse engineer, decompile, or disassemble the SOFTWARE PRODUCT, except and only to the extent that such activity is expressly permitted by applicable law notwithstanding this limitation.

i.e. you are prohibited from decompiling the source code!

Clearly they're talking about the non open source parts