Wikibase is made up of multiple components, some of which have sub components.

The top level Mediawiki extensions are:

md_docs_components_repo (in the repo directory)
- md_docs_components_view (in the view directory)
md_docs_components_client (in the client directory)
md_docs_components_lib (in the lib directory)
md_docs_components_data-access (in the data-access directory)

The primary development of these extensions takes place in Wikibase.git on Wikimedia Gerrit.

Wikibase also makes use of multiple libraries installed via Composer. See md_docs_components_libraries