Reader-added tags include "Cirno" (since Mizuki-san apparently forgot), "The paper umbrella's gonna sing", and "Guwange" (since the handwriting on the screen in panel 4 makes ใใใใ look like ใใใใ).
Sang the Ending Too
Gurenge
A little before Sanae-san returns home...
She's still singing.
There was a little kid out there?Maybe she was being your audience?Okay, then.Guess I'll sing "Gurenge" as favor to 'em.