For all practical purposes, the terms "free software" and "open source" are equivalent - the difference is political (which still matters of course). The source

For all practical purposes, the terms "free software" and "open source" are equivalent - the difference is political (which still matters of course). The source code doesn't have to be publicly available with either, but every user must have access to it on request and they may redistribute it, so practically it usually becomes publicly available anyway.