1. Git repositories on android

https://android.googlesource.com/

1.1. Android Make Build System

android / platform / build
https://android.googlesource.com/platform/build/

This is the Makefile-based portion of the Android Build System.

android / platform / build / refs/heads/main
https://android.googlesource.com/platform/build/+/refs/heads/main

android / platform / build / refs/heads/main / . / envsetup.sh
https://android.googlesource.com/platform/build/+/refs/heads/main/envsetup.sh

android / platform / build / refs/heads/android14-release
https://android.googlesource.com/platform/build/+/refs/heads/android14-release

android / platform / build / refs/heads/android14-release / . / envsetup.sh
https://android.googlesource.com/platform/build/+/refs/heads/android14-release/envsetup.sh

source ./build/make/envsetup.sh
hmm

Run "m help" for help with the build system itself.
Invoke ". build/envsetup.sh" from your shell to add the following functions to your environment:
- lunch:      lunch <product_name>-<build_variant>
              Selects <product_name> as the product to build, and <build_variant> as the variant to
              build, and stores those selections in the environment to be read by subsequent
              invocations of 'm' etc.
- tapas:      tapas [<App1> <App2> ...] [arm|x86|arm64|x86_64] [eng|userdebug|user]
              Sets up the build environment for building unbundled apps (APKs).
- banchan:    banchan <module1> [<module2> ...] [arm|x86|arm64|x86_64|arm64_only|x86_64only] \
                      [eng|userdebug|user]
              Sets up the build environment for building unbundled modules (APEXes).
- croot:      Changes directory to the top of the tree, or a subdirectory thereof.
- m:          Makes from the top of the tree.
- mm:         Builds and installs all of the modules in the current directory, and their
              dependencies.
- mmm:        Builds and installs all of the modules in the supplied directories, and their
              dependencies.
              To limit the modules being built use the syntax: mmm dir/:target1,target2.
- mma:        Same as 'mm'
- mmma:       Same as 'mmm'
- provision:  Flash device with all required partitions. Options will be passed on to fastboot.
- cgrep:      Greps on all local C/C++ files.
- ggrep:      Greps on all local Gradle files.
- gogrep:     Greps on all local Go files.
- jgrep:      Greps on all local Java files.
- jsongrep:   Greps on all local Json files.
- ktgrep:     Greps on all local Kotlin files.
- resgrep:    Greps on all local res/*.xml files.
- mangrep:    Greps on all local AndroidManifest.xml files.
- mgrep:      Greps on all local Makefiles and *.bp files.
- owngrep:    Greps on all local OWNERS files.
- rsgrep:     Greps on all local Rust files.
- sepgrep:    Greps on all local sepolicy files.
- sgrep:      Greps on all local source files.
- tomlgrep:   Greps on all local Toml files.
- pygrep:     Greps on all local Python files.
- godir:      Go to the directory containing a file.
- allmod:     List all modules.
- gomod:      Go to the directory containing a module.
- bmod:       Get the Bazel label of a Soong module if it is converted with bp2build.
- pathmod:    Get the directory containing a module.
- outmod:     Gets the location of a module's installed outputs with a certain extension.
- dirmods:    Gets the modules defined in a given directory.
- installmod: Adb installs a module's built APK.
- refreshmod: Refresh list of modules for allmod/gomod/pathmod/outmod/installmod.
- syswrite:   Remount partitions (e.g. system.img) as writable, rebooting if necessary.
Environment options:
- SANITIZE_HOST: Set to 'address' to use ASAN for all host modules.
- ANDROID_QUIET_BUILD: set to 'true' to display only the essential messages.
...

android / platform / build / refs/heads/android15-release
https://android.googlesource.com/platform/build/+/refs/heads/android15-release

android / platform / build / refs/heads/android15-release / . / envsetup.sh
https://android.googlesource.com/platform/build/+/refs/heads/android15-release/envsetup.sh

1.2. Android Open Source Project Code Review

References

[1] Yongqiang Cheng, https://yongqiang.blog.csdn.net/