As it was described, "This flag tells Perl to interpret the supplied string as a vector of integers, one for each character in the string. Perl applies the format to each integer in turn, then joins the resulting strings with a separator (a dot . by default)"

and it's actually as rjt said,"Perl interprets each character in the string as its index in your character set."

it's "index",not the number in the string.

Um, whoa :) but it also says This can be useful for displaying ordinal values of characters in arbitrary strings , so to review all it says:
* interpret the supplied string (argument is string)
* as a vector of integers (list of integers),
* one for each character in the string (character by character, integer by integer).
* ordinal values of characters in arbitrary strings (ordinal means numeric, means ordinal values of chracters )
*  printf "%vd", "AB\x{100}";           # prints "65.66.256" (A is 65, B is 66, \x{100} is 256 )

I suppose its better say/link ordinal (ord) values of characters (chr) and give explicit chr/ord example

Or say ...interpret supplied string as list of integers seperated by a dot. Each character is a positive integer, the ordinal(ord) value of the character (chr).

$ perl -le " printf qq{v%vd\n}, join q//, map {chr $_} 1000, 44000, 99
+000 , 12 "
v1000.44000.99000.12

$ perl -le " printf qq{v%vd\n}, v3.14.16.5 "
v3.14.16.5

$ perl -le " printf qq{v%vd\n}, v1.2.3 "
v1.2.3

$ perl -le " printf qq{v%vd\n}, chr(1).chr(2).chr(3) "
v1.2.3

$ perl -le " print q{v}, join q{.}, ord(chr 1), ord(chr 2), ord(chr 3)
+  "
v1.2.3

$ perl -MData::Dump -e " dd(join q//, chr 1, chr 2, chr 3 ) "
"\1\2\3"

$ perl -le " printf qq{v%vd\n}, qq{\1\2\3} "
v1.2.3

$ perl -le " printf qq{bits are %0*v8b\n}, q{ }, q{123}; "
bits are 00110001 00110010 00110011

$ perl -le " printf qq{bits are %0*v8b\n}, q{-}, q{123}; "
bits are 00110001-00110010-00110011

$ perl -le " print q{bits are }, join q{-}, unpack q{(B8)*}, q{123} "
bits are 00110001-00110010-00110011
[download]

I suppose more linking to glossary would be good in all the pod or perlmonks :)  [doc://perlglossary#vector], [doc://perlglossary#v-string], [doc://perlglossary#ordinal], [doc://perlglossary#string], [doc://perlglossary#character] vector, v string, ordinal, string, character

Thank you. I think what you wrote should be included in perldoc to help people really understand this flag.