Snap connect local themes

instructions.txt

The folder would looks like that:

.
├── local-source
│   └── share
│       ├── icons
│       │   └── oomox-CustomOneHalf

│       └── themes
│           └── oomox-CustomOneHalf
└── snap
│   └── snapcraft.yml
└── setup.sh

setup.sh

#!/bin/bash
for i in $(snap connections | grep gtk-common-themes:gtk-3-themes | awk '{print $2}'); do
    sudo snap connect $i my-local-themes:gtk-3-themes
done

snapcraft.yml

name: my-local-themes # you probably want to 'snapcraft register <name>'
base: core18 # the base snap is the execution environment for this snap
version: '0.1' # just for humans, typically '1.2+git' or '1.3.2'
summary: My local themes
description: |
  My local themes

grade: devel # must be 'stable' to release into candidate/stable channels
confinement: devmode # use 'strict' once you have the right plugs and slots

slots:
  gtk-3-themes:
    interface: content
    source:
      read:
        - $SNAP/share/themes/oomox-CustomOneHalf
        - $SNAP/share/icons/oomox-CustomOneHalf

parts:
  theme-files:
    source: local-source/
    plugin: dump