Codesearch is very handy but cannot search inside packaging repositories. Here's a way to grep on Anonscm: 

   1 #!/bin/bash
   2 # arguments: <packaging project name> '<search string>' '<path glob>'
   3 # example: ssh anonscm.debian.org ./gitgrep collab-maint Maintainer 'debian/*'
   4 
   5 set -u
   6 projname="$1"
   7 searchstring="$2"
   8 path_glob="$3"
   9 repo_cnt=0
  10 
  11 for repodir in /git/$projname/*.git; do
  12   echo -e "\n$repodir\n"
  13   cd $repodir
  14   nice ionice git grep -e "$searchstring" HEAD -- "$path_glob"
  15   ((repo_cnt++))
  16 done
  17 echo "$repo_cnt repos searched"