UL943 governs GFCI in the US, with Mexico/Canada having similar specs, and I believe EN specs are similar.
- 2003 update to improve surge suppression to protect components.
- 2006 updated to detect some miswiring
- 2015 added automated testing and a whole host of required fault detection w.r.t. the proper operation of the circuit. Newer GFCI should be much safer than old ones w.r.t. guaranteed operation. Self check is once every 90 minutes.
GFCI outlets have more stringent requirements on what happens when a fault it detected compared to GFCI breakers, but most new breakers on the market appear to be adapted the more rigid requirement to disconnect power, not just indicate a failure.
Was looking at some of the controller chips and they will even detect ground/neutral faults, and will check for failures more often.