As I understand (do the same now) - nothing
and unfortunately not only project folder, but whole workspace (including hidden folders)
if You enable display hidden files (on windows) or run on (Linux, MacOS)
You will see - some hidden folders, this folders not empty and have data common for all Your projects
are You just need - add something to .gitignore?
If You want save (and than retrieve) full status - store whole .metadata
I can't tell You more - all look, like You can store only selected project folder, and I have experience - transfer Jobs between my computers by this way, all was fine, but I do not have experience - what could be potential problem if do this.
Think Talend team do not answer for this question by clean reasons :-), so wait - may be somebody other answer.
I use Git to track projects within my Talend workspace. I currently use Atlassian's Bitbucket Server to host my repo's. I also use Atlassian Sourcetree in order to perform commits, branching and merging, it works very well.
With regards to .gitignore, I use the following:
*.screenshot /temp code/routines/system/
I have had no problems at all with it, and it works fine.
In order to setup a new repository, here is what I typically do:
On the other hand, you can create your project in Talend, and when ready to push to git, do it the other way by creating a git repository using existing files.
* It is fine to commit while Talend is still open, however I have found that when closing Talend, it makes changes to certain files and obviously Git then sees these file changes. I like to keep my commits clean and reduce the need for any unnecessary commits.
Hope this helps!