This test program defines a Python f-string. The colon character (:) is used to specify a format specifier, i.e., ",". This tells Python to format the number with comma separators for every thousand.

[3.11] gh-104018: disallow "z" format specifier in %-format of byte strings (GH-104033) #74069 Usage Workflow file Triggered via pull request May 1, 2023 19:47 miss-islington opened #104058 ...