There is no information available on the Ryanair website, it just says you must have it available. Here is the link to FR COVID travel information:
https://www.ryanair.com/ie/en/useful...virus-covid-19
I've not travelled on FR to a destination where I’ve needed to have my paperwork checked, so can’t offer any insight. Perhaps head to the FR information/sales desk when you arrive at the airport. Depending on your route, the checks may be carried out at the gate.