Migration Group Not showing in UI I am trying to migrate users table from drupal 7 to drupal 8 for that i have created custom migration module and create two file in config/install folder with the following names

custom_migration.migration_group.open.yml
custom_migration.migration.custom_user.yml

and User.php in Plugin/migrate/source for mapping fields.
The following showing content for custom_migration.migration_group.open.yml
id: open
label: Open Migration
description: Custom Migration user table form drupal 7 to drupal 8.
source_type: Drupal 7
source:
  key: drupal_7
dependencies:
  enforced:
    module:
      - custom_migration

Following Content is from custom_migration.migration.custom_user.yml
id: custom_user
label: Custom user migration
migration_group: open
source:
 plugin: custom_user
destination:
 plugin: entity:user
process:
 uid: uid
 name: name
 pass: pass
 mail: mail
 status: status
 created: created
 changed: changed
 access: access
 login: login
 timezone: timezone
 langcode: language
 preferred_langcode: language
 preferred_admin_langcode: language

When i enable the module it should show migration group in Structure-&gt;Migration . But it is not showing. Any idea why?
The filenames are wrong - they need to be migrate_plus.migration.*, not custom_migration.migration.*. The first component of a configuration entity filename is the module that defines the entity type, not the module defining the entity instance.