Misterious TemplateExtensions Feature

Question

In SharePoint Online, as part of the Modern Team site, there is a TemplateExtensions Web feature with the ID de12eebe-9114-4a4a-b7da-7585dc36a907. This feature does not exist even in SharePoint 2019.

Does anyone know what this feature is supposed to do? I could not find any documentation describing it. I have checked if this feature exusted as part of a classic Team site and it it's not present there. So I am curious what this does exactly.

This is how I have retrieved this feature:

Get-PnPFeature -Scope Web 

Answer 1

TemplateExtensions (de12eebe-9114-4a4a-b7da-7585dc36a907) is a hidden feature that is responsible for applying site Designs (site scripts) to Modern Team sites and Communication sites. This feature is activated by default on these sites.

When this feature is activated and there are pending site desigs, these are run and the logs wil lbe stored in the hidden list /_catalogs/wte.

If /_catalogs/wte does not exist, it will be created by the TemplateExtensions feature. If there are no pending site designs, this feature does virtually nothing.

After site creation script actions are initialized and processed – as each are run, they are saved to a local /_catalogs/wte list and rendered in progress panel.