Just generic/broken icons are shown for devfiles in dashboard:

That's probably because raw.github doesn't return correct headers for the svg to be "rendered", or something like that
I believe, that the solution would be to append ?sanitize=true to the URL.

For example:

• https://raw.githubusercontent.com/redhat-developer/codeready-workspaces/master/ide/codeready-ide-stacks/src/main/resources/stacks-images/type-php.svg?sanitize=true
• instead of https://raw.githubusercontent.com/redhat-developer/codeready-workspaces/master/ide/codeready-ide-stacks/src/main/resources/stacks-images/type-php.svg

Sidenote/question: Are air-gap env scripts cahing these icons somewhere and modifying them in devfiles meta.yaml?