Feat Formatting Question

[chopswil]

not sure if this is the correct forum but here it is

some feats uses commas to separate prerequisites Weapon Master's Handbook Overwatch Vortex but others use semicolons as in Weapon Master's Handbook Ascetic Strike

why the difference?

[CalethosVB]

And/or.

Bringing Christmas (general)
Prerequisites: Sing (Carol), Play (Guitar), Cook (Dinner), or Bard 3; Flurry of Blows class feature

This says you have to have Flurry of Blows and at least one of those other things.