Part of an event called Sternfahrt where cyclists protest for policy changes by taking over the city on 20 routes covering 2000 km of public roads.
some infos in german: https://berlin.adfc.de/pressemitteilung/adfc-sternfahrt-medienkit
translation to english: https://berlin-adfc-de.translate.goog/pressemitteilung/adfc-sternfahrt-medienkit?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=wapp
The speed limit used to be higher though, originally it was nonexistent. Point was to estimate what the highest throughput of people in cars that highway has ever seen.
Point taken, you’re correct.