It allows you to store links (title & language of the page, a pdf of the page, assign tags, to include them in collections), it has a very simple (moderated) comment system, set status of the link (online: direct link, offline: replace link by a webarchive one) a lightweight ui (remember: no js), multi-accounts (permissions), translations, some rudimentary stats and some other things (access a random page!).
Got burned with this by cal.com self-hosted version: https://blog.vasi.li/cal-com-is-making-me-lose-faith-in-the-...