A [matrix](#matrix) project, code [here](https://github.com/opentower/populus-viewer). It looks like it's edging its way towards being [open-source](#open source) [federated](#federation) [hypothes.is](#hypothes.is). I am watching with great hopes. Currently I think it only does [PDFs](#pdf)? And inserting anchors into HTML where no anchors exist is, to some extent, The Hard Part...