Route Groups are a folder convention that let you organize routes by category or team.
A route group can be created by wrapping a folder's name in parenthesis: (folderName).
This convention indicates the folder is for organizational purposes and should not be included in the route's URL path.

/cart that uses app/(shop)/layout.js to /blog that uses app/(marketing)/layout.js. This only applies to multiple root layouts.(marketing)/about/page.js and (shop)/about/page.js would both resolve to /about and cause an error.layout.js file, make sure your home route (/) is defined within one of the route groups, e.g. app/(marketing)/page.js.