After shunning the spotlight for years, the singer-songwriter Phoebe Bridgers has returned on her own terms—with an improbably intimate arena show and some introspective new ballads.

The indie artist has played a string of surprise, small-venue shows with no phones allowed, prompting fans to piece together clues about a potential upcoming album.

Phoebe Bridgers played eight unreleased songs at Madison Square Garden at a show that required 18,000 people to lock up their phones — and it worked.