Bug#927472: The units of duration are not explained. Microseconds?

[積丹尼 Dan Jacobson]

Package: grub2-common
Version: 2.02+dfsg1-16
Severity: wishlist
File: grub2-common

(info "(grub) play")

 -- Command: play file | tempo [pitch1 duration1] [pitch2 duration2] ...

The units of duration are not explained. Microseconds?