Add fork description and goals to top of README

README.md

@@ -10,8 +10,43 @@
 [gitlab-ci-master-badge]: https://gitlab.com/timvisee/send/badges/master/pipeline.svg
 [repo-license-badge]: https://img.shields.io/github/license/timvisee/send.svg
 
-Based on Mozilla's [Firefox Send](https://github.com/mozilla/send),
-with branding removed.
+A fork of Mozilla's [Firefox Send][mozilla-send].
+Mozilla discontinued Send, this fork is a community effort to keep the project
+up-to-date and alive.
+
+- Forked [at][fork-commit] Mozilla's latest public version
+- _Mozilla_ & _Firefox_ branding [is][remove-branding-pr] removed so you can legally self-host
+- Kept compatible with [`ffsend`][ffsend] (CLI for Send)
+- Dependencies have been updated
+- Mozilla's [changes][mozilla-patches] since the fork have been selectively [mozilla-patches-pr][merged]
+- Mozilla's experimental report feature, download tokens, trust warnings and FxA changes are not included
+
+Find an up-to-date Docker image here: [docs/docker.md](docs/docker.md)
+
+Find the original archived project by Mozilla [here][mozilla-send].
+The [`mozilla-master`][branch-mozilla-master] branch holds the `master` branch
+as left by Mozilla.
+The [`send-v3`][branch-send-v3] branch holds the commit tree of Mozilla's last
+public version, which this fork is based on.
+The [`send-v4`][branch-send-v4] branch holds the commit tree of Mozilla's last
+experimental version which was still a work in progress (featuring file
+reporting, download tokens, trust warnings and FxA changes), this has
+selectively been merged into this fork.
+
+Thanks [Mozilla][mozilla] for building this amazing tool!
+
+[branch-mozilla-master]: https://gitlab.com/timvisee/send/-/tree/mozilla-master
+[branch-send-v3]: https://gitlab.com/timvisee/send/-/tree/send-v3
+[branch-send-v4]: https://gitlab.com/timvisee/send/-/tree/send-v4
+[ffsend]: https://github.com/timvisee/ffsend
+[fork-commit]: https://gitlab.com/timvisee/send/-/commit/3e9be676413a6e1baaf6a354c180e91899d10bec
+[mozilla-patches-pr]: https://gitlab.com/timvisee/send/-/merge_requests/3
+[mozilla-patches]: https://gitlab.com/timvisee/send/-/compare/3e9be676413a6e1baaf6a354c180e91899d10bec...mozilla-master
+[mozilla-send]: https://github.com/mozilla/send
+[mozilla]: https://mozilla.org/
+[remove-branding-pr]: https://gitlab.com/timvisee/send/-/merge_requests/2
+
+---
 
 **Docs:** [FAQ](docs/faq.md), [Encryption](docs/encryption.md), [Build](docs/build.md), [Docker](docs/docker.md), [Metrics](docs/metrics.md), [More](docs/)