itch.io

You need to

launch Terminal, then type or copy/paste

chmod +x [including a space after the x]

then drag the app you need to change the perms straight onto the Terminal window, which will fill in the correct path

hit Backspace once, as the last task will add an unnecessary space

Then you need to add the sub-path to the actual executable inside the app, so copy this & paste it onto the end of your current Terminal line /Contents/MacOS/*

Hit Enter