Currently, the Veloren server browser is maintained by the Veloren Developer team.
In order for your server to be listed on the public server browser, you will need to file a ticket on the Veloren Developer team gitlab. This will require you to make an account with Gitlab (a separate service).
The link to make a request with the Veloren developer team is:
https://gitlab.com/veloren/serverbrowser/-/issues/new?issuable_template=New%20Server
For further questions regarding the public server listing, contact the Veloren Developer team on Discord: https://discord.gg/veloren