A hidden backup button battery is in the Canon T2i, possibly also in Fuji X-T3?

[Jay60p]

My old Canon T2i has stopped remembering the date and time if the battery is removed.

It Turns out there is a hidden internal backup rechargeable “button” battery, not mentioned in the manual.

Luckily it is accessible, as seen here:
https://www.ifixit.com/Guide/Canon+EOS+Rebel+T2i+Clock+Battery+Replacement/139543

The battery is a Seiko MS614SE, not to be found in Canon’s support pages.

After some effort I found a supplier that ships it in the USA:
https://eu.mouser.com/en/ProductDetail/Seiko-Instruments-Micro-Energy/MS614SE?qs=vrQyzjTsotmt1bmGskqEPQ%3D%3D

I will see if the new button battery fixes the problem. There may be more to it.

There is also a similar thing going on with Fuji cameras.
Starting earlier this year, my X-T3 will reset & lose my settings & the date
If the camera is not turned off before removing the battery.

There is a YouTube about it here:
https://www.youtube.com/watch?v=3vOv-xjUtzw

In the X-T3,  I do not see an access to a button battery like there is in the Canon T2i.