e-five

They could, yes. Afaik no extra work was needed on lemmy’s side once Mbin changed to report moderators in the same manner (aside from some kind of activity which triggered a refresh of the data)

However, looking at peertube, it looks like they already are using the attributedTo field for the group with a person, which is different from the FEP. For the channel you link in the OP specifically:

"attributedTo": [
  {
    "type": "Person",
    "id": "https://tilvids.com/accounts/thelinuxexperiment"
  }
]

It’s possible PeerTube could change to make a /moderators endpoint and respond with that as the FEP suggests, or Lemmy and other software to change to accept this array of actor types instead. I’m not sure who decides these things or if there is an evangelist for FEPs, It’s possible this was already discussed on the peertube github as well, I didn’t look through all the past issues as there are quite a lot

An ActivityPub group actor defining its moderators is a specific implementation of the AP protocol. You can find the spec details lemmy uses here. An Mbin contributor recently implemented this to line up with Lemmy, but whether other fediverse software do or will is up to them, as it’s more of a community proposal than an official implementation of the spec. So when you see no moderators from other software, they likely just do not implement the linked FEP