It seems as if this project has gone from open source to a closed source service ? [ https://github.com/replit/jsrepl ]
Are Facebook, Google, and all the other name brands you are using to promote your product using your proprietary service, or the older open source stuff? If you have gone closed source, you should only be using names that are using the proprietary product.
It seems like putting "Open Source" on your front page in a big headline is a bit misleading if you are now a proprietary service. Labeling "Open Source" as a key feature seems disingenuous if you used to be open source but are no longer. If the case now is just that you use open source software, I don't think "Open Source" as headline is appropriate, as that is true of almost any company. The implication with listing "Open Source" as a headline is that your product is open source.