You aren&#x27;t profiting off your work, you&#x27;re piggybacking off their work with just enough tweaks to sell it. Go write your own software if you want to profit off your work. Then you won&#x27;t have to deal with the copyleft licenses because you won&#x27;t be using anyone else&#x27;s work.<p>Which is the exact purpose of a copyleft license.