Hi @tjonas331,

Those buttons are designed for deleting the caches.

For example, If you do some change in phrases, you should delete the phrase caches via the [Delete Phrase Cache] button to see the new value of the phrase. If you can't find some phrase, click on the [Rebuild Phrases] button, then navigate to Dashboard > Forums > Phrases admin page, search the phrase you were not able to find before. 

More info here: https://wpforo.com/docs/root/translation/quick-translation-phrases/

In case if you put some additional CSS code in the "Custom CSS code" textarea, located in the Dashboard > Forums > Settings > Style Tab and don't see any changes on the frontend, you should click on the [Delete All Caches]. 

If you see some problem with the forum statistic, e.g. the topic count is not changed, you should use the [Update Forums Statistic] button. 

In case if you change the group of the user and don't see some changes, click on the [Delete User Cache] and [Update Users Statistic] buttons. 

In any case, you'll also need to press CTRL+F5 (twice) on the forum frontend before checking to reload updated JS/CSS files.