ZHA quirks with Ubuntu snap

I’m trying to add a basic ZHA quirk but I don’t understand where the various additions go. I’m looking at e.g. ZHA how to install custom quirk?

I added the following to configuration.yaml (not sure if this is the correct place):

  enable_quirks: true
  custom_quirks_path: /config/zha_quirks

but I’m getting an error:
Invalid config for [zha]: not a directory for dictionary value @ data[‘zha’][‘custom_quirks_path’]. Got ‘/config/zha_quirks’. (See /var/snap/home-assistant-snap/541/configuration.yaml, line 13).

Is the ‘/config’ supposed to be an actual directory? Or an alias to the ‘configuration directory’? And am I correct in assuming the ‘configuration directory’ is /var/snap/home-assistant-snap/current on Ubuntu?

Questions on quirks are quite common but none of the answers appear to specify any actual pathnames or filenames so am I missing something?