chore: import upstream snapshot with attribution

docs/api_reference/README.md

@@ -0,0 +1,90 @@
+# MLflow API Documentation
+
+This directory contains the MLflow API reference. The source code (`.rst` files) is relatively minimal, as the API docs are mainly populated by docstrings in the MLflow Python source.
+
+## Building the docs
+
+First, install dependencies for building docs as described in the [Environment Setup and Python configuration](https://github.com/mlflow/mlflow/blob/master/CONTRIBUTING.md#environment-setup-and-python-configuration) section of the main MLflow contribution guide.
+
+Building documentation requires [Pandoc](https://pandoc.org/index.html). It should have already been
+installed if you used the automated env setup script
+([dev-env-setup.sh](https://github.com/mlflow/mlflow/blob/master/dev/dev-env-setup.sh)),
+but if you are manually installing dependencies, please follow [the official instruction](https://pandoc.org/installing.html).
+
+Also, check the version of your installation via `pandoc --version` and ensure it is 2.2.1 or above.
+If you are using Mac OSX, be aware that the Homebrew installation of Pandoc may be outdated. If you are using Linux,
+you should use a deb installer or install from the source, instead of running `apt` / `apt-get` commands. Pandoc package available on official
+repositories is an older version and contains several bugs. You can find newer versions at <https://github.com/jgm/pandoc/releases>.
+
+To generate a live preview of Python & other rst documentation, run the
+following snippet. Note that R & Java API docs must be regenerated
+separately after each change and are not live-updated; see subsequent
+sections for instructions on generating R and Java docs.
+
+```bash
+cd docs
+make livehtml
+```
+
+Generate R API rst doc files via:
+
+```bash
+cd docs
+make rdocs
+```
+
+---
+
+**NOTE**
+
+If you attempt to build the R documentation on an ARM-based platform (Apple silicon M1, M2, etc.)
+you will likely get an error when trying to execute the Docker build process for the make command.
+To address this, set the default docker platform environment variable as follows:
+
+```bash
+export DOCKER_DEFAULT_PLATFORM=linux/amd64
+```
+
+---
+
+Generate Java API rst doc files via:
+
+```bash
+cd docs
+make javadocs
+```
+
+Generate API docs for all languages via:
+
+```bash
+cd docs
+make html
+```
+
+Generate only the main .rst based documentation:
+
+```bash
+cd docs
+make rsthtml
+```
+
+After running these commands, a build folder containing the generated
+HTML will be generated at `build/html`.
+
+If changing existing Python APIs or adding new APIs under existing
+modules, ensure that references to the modified APIs are updated in
+existing docs under `docs/source`. Note that the Python doc generation
+process will automatically produce updated API docs, but you should
+still audit for usages of the modified APIs in guides and examples.
+
+If adding a new public Python module, create a corresponding doc file
+for the module under `docs/source/python_api` - [see
+here](https://github.com/mlflow/mlflow/blob/v0.9.1/docs/source/python_api/mlflow.tracking.rst#mlflowtracking)
+for an example.
+
+> Note: If you are experiencing issues with rstcheck warning of failures in files that you did not modify, try:
+
+```bash
+cd docs
+make clean; make html
+```