I’ve actually had designers come to me with a concept for “a visual indicator that shows the user how they are progressing through the page”
I have seen those on blog and news sites, a thin horizontal bar (sometimes under the floating title) that fills as you scroll to the bottom. I don’t get it either.
Organic Maps / CoMaps is not some corporate platform, you “migrating” to them does not gain them anything. If you have a constructive suggestion, open an issue or contact them.