I updated depot tool, create a new minilayout repo:

When I workon start a new package, repo is not asking to sync.
repo sync does not extract the new package code.

Created a directory:
gwendal/cave_firmware/
Repo init with:
repo init \
-u https://chrome-internal.googlesource.com/chromeos/manifest-internal.git \
--repo-url='https://chromium.googlesource.com/external/repo.git' \
-g minilayout -b firmware-glados-7820.B

Set went fine, installing base packages, but it would not set up new packages:
cros_workon start --board cave sys-boot/depthcharge
10:11:55: INFO: Started working on 'sys-boot/depthcharge' for 'cave'


Log in older minilayout repo, the expected behavior works:
Compare a samus repo:
cros_workon start --board samus chromeos-base/autotest-tests-cryptohome
WARNING: 'portageq envvar PORTDIR_OVERLAY' is deprecated. Use 'portageq repositories_configuration' instead.
Please run "repo sync" now.
INFO    : Started working on 'chromeos-base/autotest-tests-cryptohome' for 'samus'

With newer one:
cros_workon start --board cave chromeos-base/autotest-tests-cryptohome
Usage: loman add [options] <name> <--workon | <path> --remote <remote> >

loman: error: No project named 'chromiumos/third_party/autotest' in the default manifest.
cros_workon: Unhandled exception:
Traceback (most recent call last):
  File "/mnt/host/source/chromite/bin/cros_workon", line 164, in <module>
    commandline.ScriptWrapperMain(FindTarget)
  File "/mnt/host/source/chromite/lib/commandline.py", line 834, in ScriptWrapperMain
    ret = target(argv[1:])
  File "/mnt/host/source/chromite/scripts/cros_workon.py", line 89, in main
    use_workon_only=options.workon_only)
  File "/mnt/host/source/chromite/lib/workon_helper.py", line 562, in StartWorkingOnPackages
    self._AddProjectsToPartialManifests(new_atoms)
  File "/mnt/host/source/chromite/lib/workon_helper.py", line 494, in _AddProjectsToPartialManifests
    cros_build_lib.RunCommand(cmd, print_cmd=False)
  File "/mnt/host/source/chromite/lib/cros_build_lib.py", line 619, in RunCommand
    raise RunCommandError(msg, cmd_result)
chromite.lib.cros_build_lib.RunCommandError: return code: 2; command: loman add --workon chromiumos/third_party/autotest
cwd=None

BTW, in loman.py, I can see some code like "active_manifest == 'minilayout.xml'"
But none of my minilayout repo uses minilayout.xml. I can not even find this file.

Calling the loman command manually:
 loman add --workon chromiumos/platform/ec
Usage: loman add [options] <name> <--workon | <path> --remote <remote> >

loman: error: No project named 'chromiumos/platform/ec' in the default manifest.

Although it is in .repo/manifests/external_full.xml, included by .repo/manifest.xml.
Interestingly, the manifest.xml file for cave minilayout is different from the samus minilayout, where .repo/manifest.xml there is more complete.