It is an Instagram-like client from nostr:nprofile1qqs04xzt6ldm9qhs0ctw0t58kf4z57umjzmjg6jywu0seadwtqqc75spz4mhxue69uhhyetvv9ujuerpd46hxtnfduhsz9mhwden5te0wfjkccte9ec8y6tdv9kzumn9wshszxnhwden5te0wpuhyctdd9jzuenfv96x5ctx9e3k7mf0dv4ph5.
You can sign in using your existing nsec but I would t recommend that. Use a signing app like Amber if you are on Android or Nostr Connect. If you need further help with using signing apps you can ask the Nostr community.