Sorry for the delay. It isn’t clear to me why this interface should be auto-connected for all snaps that declare it. Can you describe the rationale in more detail/ (I was thinking that one could install this snap and then connect it if you wanted add more dictionaries).
That said, the name of the slot is following the conventions laid out in Auto-connection for gnome-3-24 content interface. Specifically, the snap is using:
slots:
hunspell-dictionaries-1-3-1604:
content: hunspell-dictionaries-1-3-1604
interface: content
read:
- $SNAP/usr/share/hunspell
/usr/share/hunspell only contains data files, so this actually feels more like the icon themes as discussed here: Auto-connection of gtk3-themes, icon-themes, and sound-themes interfaces.
Are the data files specific to libhunspell 1.3 or are they meant to be compatible across various releases of hunspell? Should your snap ship libhunspell for other snaps to use?