Now that the "full" (Studio Link) versions of Photo, Designer and Publisher are all released (excellent news, by the way) I'd like to bump this question, which I originally posted in the Publisher Private Beta forum
The Publisher Photo Persona still lists Filters<Plugins but nothing is listed and available. I wonder whether the link to installed photo plug ins is going to be "activated" at some point, or not?
Certain tools and features have been kept app-specific; such as the Liquify Persona in Photo, the Export Persona in Designer etc and Plugins are part of this.
Of course, you can still use the 'Edit in Affinity Photo' option to access the full app, but AFAIK we don't plan on supporting Plugins in Publisher currently. I'll raise this menu entry with our devs now, thanks for your report!