Hi @regis and thank you for the great effort you provide to the community.
Yes I have created a test “about” page, called it “about.html” and put it in a folder called “static_templates” under /lms/templates/ path and modified the url in the config.yml at the root of the indigo theme.
I could view the file “about.html” but with no styling at all.
You should not modify the url in the INDIGO_FOOTER_NAV_LINKS. This url refers to the url that will be shown in your browser. In your case, it’s “/about”.