We know nothing at all about what the Homeworlds Clans are doing at this stage. Heck, we don't even know if they're still there right now.
That being said, the only Inner Sphere Clans around who use ProtoMechs since the Wars of Reaving are basically the Horses and Ravens. The way Protos were largely subverted by the Society during the WoR put the final nail in their coffin as a concept for every Clan that was hesitant about embracing them (Wolves and Ghost Bears), or Clans that had already chosen to abandon them (Jade Falcons). The Sea Foxes didn't have much interest either, beyond maybe selling any they might have had. This left only the Horses and Ravens--both of whom saw their potential, not only as combat units, but also a way to recoup washouts from their aerospace sibkos who would otherwise become techs.
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