Is this strictly true? Our current v5.3.6 winning entry has text on the map, including a prominent “M” icon, and lots of prior winners include “TiddlyWiki” even though the rules are explicit that this is only optional… There were entries at v5.2.4 with additional text that didn’t get any push-back, as far as I know.
But yes — we have generally resisted having a banner that incorporates slogans or text that looks like it needs to be read (in order to take in the meaning of the version banner). And whatever’s in a version banner needs to look good and retain its value even at pretty small sizes.