Hi
I think you're looking in the right place and agree it could be more obvious but see the last update line where the date is in italics e.g.
The update only says:
xertetoolkits_update_3.10
Stable release of Xerte Online Toolkits 3.10 released on Jue 30, 2021 including latest patches.
Contains only the changes since June 30, 2021
Only deploy on an existing 3.10 installation.
Last update 2022-03-04
and the full download says:
xertetoolkits_3.10
Stable release of Xerte Online Toolkits 3.10 released on June 30, 2021 including latest patches.
Last update 2022-03-04
It's those last update lines that tell you the date of the latest code in that download and it's in yyyy-mm-dd format.
HTH
Ron