@Suiseiseki The open source definition is an almost exact copy of the Debian Free Software Guidelines. GNU accepts free software require "that you change the name of the modified version [or] remove a logo", which the DFSG and OSD do not (seem to) allow for. One might therefor argue open source is in fact more strict in demanding freedom of the software as a whole than free software is.
https://people.debian.org/~bap/dfsg-faq.html#not_just_code
https://www.gnu.org/philosophy/free-sw.html#packaging
Note that the three organisations disagree on the approval of several licenses: https://en.wikipedia.org/wiki/Comparison_of_free_and_open-source_software_licenses#Approvals