I installed the latest version of Orbot via Github.
At the first launch it was reported that certificates were not up to date.
After my permission something was downloaded.
After that Orbot worked perfectly.
To check, if I can undo the changes, I uninstalled Orbot and reinstalled.
At start this time there was no report regarding certificates.
However, under user-certificates is not an entry.
So has Orbot updated the system certificates?