It doesn’t really explain what a “kit” is….
kit is usally like
js + css +font files
it comes down to if you want to include in say your own bundler or just let the browser do it stuff
or maybe you only want a particiular part, just use a kit as dorset suggested
hi dev/build runs fine but it often gives me blue entries with for example Field SiteTree.ClassName: changed to varchar(255) default 'Page' check ("ClassName" in ('SilverStripe\CMS\Model\SiteTree', 'Page', 'LayoutPage', etc .. all is fine but i want to get rid of blue entries in dev/build. any tips?
Not really. They're informational messages
They'd usually only show up when something is changed (eg. objects or page classes are added)