* Refactor documentation to make a simpler and shorter [Tutorial - User Guide](https://fastapi.tiangolo.com/tutorial/) and an additional [Advanced User Guide](https://fastapi.tiangolo.com/advanced/) with all the additional docs. PR [#887](https://github.com/tiangolo/fastapi/pull/887).
* Tweak external links, Markdown format, typos. PR [881](https://github.com/tiangolo/fastapi/pull/881).
* Fix bug in tutorial handling HTTP Basic Auth `username` and `password`. PR [865](https://github.com/tiangolo/fastapi/pull/865) by [isaevpd](https://github.com/isaevpd).
* Fix handling form *path operation* parameters declared with pure classes like `list`, `tuple`, etc. PR [856](https://github.com/tiangolo/fastapi/pull/856) by [nsidnev](https://github.com/nsidnev).
* Add request `body` to `RequestValidationError`, new docs: [Use the `RequestValidationError` body](https://fastapi.tiangolo.com/tutorial/handling-errors/#use-the-requestvalidationerror-body). Initial PR [853](https://github.com/tiangolo/fastapi/pull/853) by [aviramha](https://github.com/aviramha).
* Update [External Links](https://fastapi.tiangolo.com/external-links/) with new links and dynamic GitHub projects with `fastapi` topic. PR [#850](https://github.com/tiangolo/fastapi/pull/850).
* Fix Peewee `contextvars` handling in docs: [SQL (Relational) Databases with Peewee](https://fastapi.tiangolo.com/tutorial/sql-databases-peewee/). PR [#879](https://github.com/tiangolo/fastapi/pull/879).
* Setup development environment with Python's Venv and Flit, instead of requiring the extra Pipenv duplicating dependencies. Updated docs: [Development - Contributing](https://fastapi.tiangolo.com/contributing/). PR [#877](https://github.com/tiangolo/fastapi/pull/877).
* Update docs for [HTTP Basic Auth](https://fastapi.tiangolo.com/tutorial/security/http-basic-auth/) to improve security against timing attacks. Initial PR [#807](https://github.com/tiangolo/fastapi/pull/807) by [zwass](https://github.com/zwass).