Is there a special install order for packages and z3c.jbot?

I have a local installation of Plone 6 classic via pip. If i checkout plone.app.contenttypes to source via mx.ini, then the overrides of some templates via z3c.jbot are broken (means: they are gone) and i see the original templates.

# mx.ini
[settings]
requirements-in = requirements-local.txt
requirements-out = requirements-local-mxdev.txt
contraints-out = constraints-local-mxdev.txt

# if i enable this, then the template overrideing doesn't work

# [plone.app.contenttypes]
# url = https://github.com/plone/plone.app.contenttypes.git
# branch=3.0.2
# requirements-local.txt
-c constraints.txt # points to -c https://dist.plone.org/release/6.0.4/constraints.txt
Plone
plone.app.upgrade
cookiecutter

# install local dev packages
-e ../project/my.theme
<!-- configure.zcml in my.theme -->
<include
    package="z3c.jbot"
    file="meta.zcml"
    />

<browser:jbot
    directory="overrides"
    layer="my.theme.interfaces.IMyThemeLayer"
    />

Has anyone a hint for the direction of debugging?

Not sure, but maybe you can debug in z3c.jbot/manager.py at master · zopefoundation/z3c.jbot · GitHub

z3c.jbot uses some mechanism to detect where the files are located. based on sys.path. With pip editable installs it is possible it has some special needs not covered yet.