You have to accept the WiFi Conditions once to use the WiFi.
WiFi Conditions: https://service.rz.tu-clausthal.de/apps/radius/policy
The configuration package is unsigned because of technical reasons. So don´t worry about that. To be assured, you can have a look at the profile in clear text form, so you can check, that it only configurates things you wish. This is also possible before installing it. You can check the planned changes by clicking on More details
You can remove the installed profile here: „Settings > General > Profiles > eduroam“ if you tap on „delete“.