Visit the String#strftime section

• https://rubyapi.org/3.2/o/time#method-i-strftime

You'll see the following text

Returns a string representation of self, formatted according to the given string format. See Formats for Dates and Times.

"Formats for Dates and Times" should link to rdoc-ref:strftime_formatting.rdoc
https://github.com/ruby/ruby/blob/a528908271c678360d2d8ca232c178e7cdd340b4/time.c#L5139