Providing translations for custom modules I'ld like to provide module specific translations for my custom modules.
I followed the instructions in https://api.drupal.org/api/drupal/core!modules!locale!locale.api.php/group/interface_translation_properties/8.

But if I install the module no translations get imported.
I've searched a lot for examples on the net, but it seems as no one else used it until now.

Here's my module "custom_module"

custom_module.info.yml:

name: 'Custom module'
version: '8.x-1.0'
core: 8.x
project: 'custom_module'
datestamp: 1434014760 
interface translation project: custom_module    
interface translation server pattern: modules/custom/custom_module/custom_module-%version-%language.po


and a "custom_module-8.x-1.0.de.po"-file with some messages in the module folder.
I had a similar problem that it didn't work but it turned out that my problem was with file permissions that weren't set correctly on the PO file I was trying to import.

I debugged it as follows:

On the following url admin/reports/translations you can see where it looks and what it looks for. (handy for debugging the tokens) Expand the status information for the available language.

Every time you change your info.yml file don't forget to rebuild cache and trigger the translation update manually.