> I am not sure what is required for the helipad to be in that list

Section 2.6: https://aim.rlp.cz/predpisy/predpisy/dokumenty/L/L-14-H/data/effective/hl2.pdf

As for the definitions themselves, that's ICAO Annex 14 Vol II (transposed into Czech national law as Regulation L-14-H).

Not that anyone would be crazy enough to use OSM as an authoritative source for this, but nevertheless.
