No. You’re probably thinking of what people refer to as “source available” which means the source is there and technically no one can stop you from looking at it but you’re not free to do whatever you want with it like you are open source stuff. It’s sort of a bad terminology but it is less.loaded than “free” which can mean “free as in beer” or “free as in speech”.

Somethings aren’t even source available either. Just because you can reverse engineer something doesn’t mean the source is available. Even JavaScript which is not compiled is not always considered source available. It is often minified and obfuscated in the browser. All variable names get replaced with junk.

In summary, open source refers to specifically to your rights to use software, not just your ability to see the source.