RBuster
I checked your demo.
The thing on linux is: shared libraries (something like a .dll on windows) can be executable too, depending on how they are programmed. The file managers try to identify those by various methods and hide the executable options on them.
The problem is: the way modern executables are compiled those file managers sometimes misinterpret and have false positives. This is typically no problem, because, unlike on windows, people do not browse to a directory with a file manager and execute stuff there. You run your stuff either through your desktop environment (start menu entries or whatever the specific linux distribution offers for its own software), or by terminal.
The file manager that I have tested (thunar) falls for the nw-executable too and does not offer to execute it. There is probably no way to get this to work reliably, because of the way chromium is required to be built.
If your customer requires this: drop the customer