https://github.com/kubevirt-ui/kubevirt-plugin/blob/main/locales/en/plugin__kubevirt-plugin.json

"Templates catalog": "Templates catalog",
"Templates project": "Templates project",

Change "Templates catalog" to "Template catalog" and "Templates project" to "Template project".

In this context, "Template" is an adjective, not a noun. Adjectives do not have plurals. Compare these with the following labels, which are correct: "Template provider", "Template name", "Template parameter".

When changes are merged, we will update the documentation.