> An open-source license is a type of license for computer software and other products that allows the source code, blueprint or design to be used, modified or shared (with or without modification) under defined terms and conditions.
https://en.wikipedia.org/wiki/Open_source
Companies have been really abusing what open source means- claiming something is "open source" cause they share the code and then having a license that says you can't use any part of it in any way.
Similarly if you ever use that software or depending on where you downloaded it from, you might have agreed not to decompile or read the source code. Using that code is a gamble.