When using the WordPress Development Environment (wpenv) links to missing asset files do not return 404 and are redirected

[azaozz]

The redirect is with 301 to the same location as the missing file but with backslash added at the end. Then the front-end is loaded. This results in errors when the missing file is js or css:

The stylesheet ​http://localhost:8889/wp-includes/css/buttons.css/?ver=5.8-beta3-51218-src was not loaded because its MIME type, “text/html”, is not “text/css”.

Happens only when the "Plain" permalinks (?p=123) are used. Changing to any other type of permalinks fixes this.