What is going on in my application. Seeing some wierd POST-request towards a URL/Endpoint I've never seen?

$ next dev
  ▲ Next.js 14.2.3
  - Local:        http://localhost:3000
  - Environments: .env.local, .env

 ✓ Starting...
 ✓ Ready in 4s
 ○ Compiling /_not-found ...
 ✓ Compiled /_not-found in 3s (775 modules)
 ✓ Compiled in 872ms (299 modules)
 POST /store/clan-tag-colors/has-update/1 404 in 4225ms
 POST /store/clan-tag-colors/has-update/1 404 in 6202ms
 POST /store/clan-tag-colors/has-update/1 404 in 2107ms
 ○ Compiling / ...
 ✓ Compiled / in 935ms (795 modules)
 POST /store/clan-tag-colors/has-update/1 404 in 773ms
undefined
Warning: Each child in a list should have a unique "key" prop.

Check the top-level render call using <TableBody>. See https://reactjs.org/link/warning-keys for more information.
    at eval (webpack-internal:///(rsc)/./components/ui/table.tsx:67:81)
 GET / 200 in 1773ms
 ✓ Compiled /favicon.ico in 362ms (538 modules)
 GET /favicon.ico 200 in 514ms
 POST /store/clan-tag-colors/has-update/1 404 in 174ms
 POST /store/clan-tag-colors/has-update/1 404 in 81ms
 POST /store/clan-tag-colors/has-update/1 404 in 263ms
 POST /store/clan-tag-colors/has-update/1 404 in 102ms