All the expo data is contained in 4 repositories or repos at expo.survex.com:
These online webpages (links above) give a much clearer view of what is going on than many git tools you may be using on your machine.
Have a look at the version history of the drawings to look at progress on getting the recent surveys uploaded, and who has been doing what on the website and handbook.
For an example, see this simple edit.
You can read or clone these repos without any control, but to write ("push") to them you will need to use ssh://firstname.lastname@example.org and set up the key exchange.
NOTE: when using git to path to a repository, always use user 'expo' as the login user (ssh://expo@...) even though within git you will be identified by your own ssh key name. This is because file permissions on the server require this.
So cavers wanting to upload their cave survey data have to use a machine on which they key is already set up. The expo laptop lives in the potato hut during expo and it is sometimes joined by the laptop 'aziraphale'. These are both loaned machines running Linux. If you want to use your own laptop then see the minimal laptop setup.
We use a distributed revision control system (git) for all the important data.
Note that we just use git: not GitHub, not GitLab, just git.
This allows many people to edit and merge their changes at the same time. This includes people still on expo and those who have returned to the UK. Also anyone who is up to date can take their laptop somewhere (e.g. topcamp) and enter data even if they have no Internet access, and the updates will be merged when they get back to civilization.
We use a version control system because this keeps track of all changes so we can roll back mistakes. We also have multiple copies of the data on multiple machines for safety.
We use git because it is now the industry standard. In the past we have used cvs, subversion and mercurial.
A version control system is inefficient for photos, GPS tracks and scanned survey notes which are large files that do not get modified. These are kept as a plain directory of files /expofiles/.