Firmware improvements are now official, with Canon publishing the new version 1.5 log of changes coming to the R5 (and equivalents to the R6 and 1DX Mark III) from features developed for the newly-released Canon R3. [Update: the software is now available for general download.]
These include improved head and eye detection, especially when part of the head is obscured by goggles, hear, shadows, etc. Also included is vehicle AF mode.
There are another dozen minor features added, but one that may be of practical use is improved in-body image stabilization when using lenses that do not have lens image stabilization.