View the original community article here
Last tested: Feb 13, 2020
You may be puzzled to see something like this on a LookML dashboard:
Essentially, in order to get your ids for your custom theme, you'll need to hit the /themes endpoint in the API.
https://docs.looker.com/reference/api-and-integration/api-reference/v3.1/theme#get_all_themes
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