All extension have this in common:

• Upload ZIP file or grab files from web (e.g. git repo)
• Read config.xml
• If config.xml is valid and the extension compatible with current version of LimeSurvey, then -- Copy files to correct folder (depends on extension type) -- Insert database row (depends on extension type)

Fetching files can happen in different ways:

• Upload ZIP
• wget ZIP from a URL
• Enter git repo
• Etc. Each method is its own subclass of this class. Each extension type can support a number of different file fetch methods.

Must work for all extension types: plugins, theme, question theme, etc.

All extension have this in common:

• Upload ZIP file or grab files from web (e.g. git repo)
• Read config.xml
• If config.xml is valid and the extension compatible with current version of LimeSurvey, then -- Copy files to correct folder (depends on extension type) -- Insert database row (depends on extension type)