Your ARL is essentially your digital signature. Sharing it gives others full access to your account. How to Find Your Own Deezer ARL
It allows third-party software (like Freezer, Deemix, or Mopidy) to stream or download music directly from Deezer's servers. deezer arl list
Deezer has implemented countermeasures:
Public ARLs are used by hundreds of people simultaneously. Deezer’s security systems often detect this "location hopping" and invalidate the token quickly. Your ARL is essentially your digital signature