- src - Compiled source code
- include - Header files
- deps - External dependencies, or ".d" dependency files
- .deps - .d dependency files
- build - build scripts
- dist - distribution files. Final compiled files
- debug - files compile in debug mode
- release - files compiled in release mode
- obj(s) - Compiled object files
- bin - Binaries, or compiled executable
- lib - library files (so, a, dll, lib), either external or compiled
- test(suite) - test suite code
- externs/ext - External dependencies
- contrib - external dependencies, or additional code not officially part of the main line
- patches - patch files to apply to build
- tools - tools used in build, but not necessarily part of final project
- doc - documents
- res - resources
Some source trees include directories for each file type, such as css, js, xml
