Lora E5 external oscillators

Hi, the wiki of the Lora E5 Dev Board states that external oscillators are used (High Speed External HSE and Low Speed External LSE), but after I ran into issues, I switched to Low Speed Internal, which resolved the problems.
After checking schematics, I could not find any external oscillators.
Are they just not in the schematic (but on the board) or is this a bug?