Hi, Bastian Blank:
>> And there's what Jeremy replied to you. We shall not endorse non-free. > > No, he just said we should prefer to use free ones. > > Endorse is something different, please read yourself > https://www.merriam-webster.com/dictionary/endorse or As your link says Endorse: to approve openly, to recommend. The use of this word is entirely correct. Cheers, Ulrike