Created attachment 158260 [details] Screenshots from Firefox 73 (Linux) and Chrome (Android). I'm using the libreoffice-online docker container (latest) https://hub.docker.com/r/libreoffice/online. Seems like its platform independent.
I can see the formula bar in a fresh LO Online master build, it must've been fixed since then, there were a couple of missing commits after the tunneled formula bar was implemented. Note that currently there's a focusing issue with the formula bar, that will be fixed in the near future.
FYI the focusing issues should mostly be gone as well.