When building cartographer on ubuntu focal, it requires libabsl-dev, so I manually backported the package, build deb myself and installed the deb package, such that my ubuntu focal system actually have libabsl-dev package.

But when using bloom I got this error:

ROS Distro index file associate with commit 'dbc7f9c9074335122cdde08048d7f51755ccdc96'
New ROS Distro index url: 'https://raw.githubusercontent.com/ros/rosdistro/dbc7f9c9074335122cdde08048d7f51755ccdc96/index-v4.yaml'
==> Generating debs for ubuntu:focal for package(s) ['cartographer']
[libabsl-dev] defined as "not available" for OS version [focal]
    rosdep key : libabsl-dev
    OS name    : ubuntu
    OS version : focal
    Data:
arch:
        - abseil-cpp
        debian:
          '*':
          - libabsl-dev
          buster: null
        fedora:
        - abseil-cpp-devel
        gentoo:
        - dev-cpp/abseil-cpp
        nixos:
        - abseil-cpp
        openembedded:
        - abseil-cpp@meta-oe
        rhel:
          '*':
          - abseil-cpp-devel
          '7': null
        ubuntu:
          '*':
          - libabsl-dev
          bionic: null
          focal: null

Is there a way to write a rosdep.yaml to solve this problem ? I have tried this one, which doesn't work:

libabsl-dev:           
  ubuntu:
    focal: libabsl-dev