about generated folders in magento 2

/var/cache: Magento cache (config, blocks, etc...)
/var/page_cache: Magento full page cache (aka FPC)
/var/generation or /generated: Auto generated Magento code (Interceptors, etc...)
/var/view_preprocessed: Static contents before processing (like CSS and processed LESS files)
/pub/static: Public static files (like JS, CSS, HTML, etc...)