Well basically anybody, but of course it has to be Xfce related. If you want to translate, a GIT account is not needed, you should read this first.
That said, please only apply for an account only if you think that you will work on Xfce for a somewhat longer time. If you know that you will only work for a couple of weeks and then never again, please consider not applying for an Xfce account but instead continue to put patches in the bug tracker.
You can first publish your code on Gitlab.com, Github.com or whatever platform to show what you have done before applying for an official Xfce account.
The limitations are not there to exclude anyone – they are there to ensure that the maintenance of accounts remains reasonable. Of course, to be clear: the Xfce sysadmins have the last word about whether or not to create an account for somebody.
The easy way to get a contributor account is to contact developers on xfce4-dev mailist or to connect to IRC channel on xfce-dev.
For a secure connection to push Git commits, the Xfce project uses SSH keys to authorize on the server.
The Xfce servers support the types RSA and ECDSA. For RSA use sufficient bits like 2048 or 4096.
When the command asks for the passphrase it is advised to set a relatively simple password. This password is used to unlock the key when you use it. For more information on how to create a pair of SSH keys, please refer to a SSH documentation or book.
Using a key without a passphrase is basically the same as writing down that random password. Anyone who gains access to your computer has gained access to every system you use that key with. The solution is to add a passphrase to the SSH key, for an extra layer of security.
See also: How to work with ssh-agent.
Now that you are finished generating your key pair, you will have two files: a private key and a public key. If you have accepted the default filename, they will be respectively $HOME/.ssh/id_rsa and $HOME/.ssh/id_rsa.pub, depending on the type of key you have specified.
The public key can be published and shall be sent when you are applying for an Xfce GIT account.