The bug-tracker is at GitHub.
Describe step by step how to reproduce the bug. If it only happens when loading a certain file, attach that file to the report. Make sure to give information about the version of widelands you use and which operating system.
Media bugs and projects are tracked in the Widelands repository, and they all carry the media label.
For the website
The bug-tracker for the website is at GitHub.
Use the link after, for reporting bugs from the website, and only from the website. Remember - to fix a bug, we need to know how can it be reproduced, where (in what part of the website) it happens and if it's a problem with style (look) of the page, what browser do you use.
For the Metaserver
Problems with internet game connections can be caused either by bugs in Widelands itself, or in the meta/relay servers. If you're unsure, just report it to Widelands.
The bug-tracker for the servers is at GitHub.