From version 2.3.4 (July 2017) to 2.4.4 (May 2019)

Remove the UUID from the first line of all config files.

Except for system.site

For system.site, the uuid needs to be updated with the uuid of the target site.

By gradually diffing as I make changes I want to discover which yml files I'd need to "play in" building a site piece by piece. Whist I could just build a site and then export/import the entire package, I wanted to gain better understanding so that I could, in future, know to deploy some pieces but not others, or to be able to make changes just to the yml files and rebuild the site entirely.

1. Selecting a new theme instead of the default

The following yml files become relevant:

In trying to build a fully repeatable Drupal 8 site build, as well as wanting to include config, modules and themes, I want to be to insert content. This will allow boiler-plate or test content to be inserted, or will allow me to quickly build out a new version of my target site.  

In the first instance I was looking for a way to insert a image into a Core Media Image node.