Missing schema file

I've recently hit the hard wall of the schema files, so I'm not really sure about the following review:

1. +++ b/config/schema/ckeditor_media_embed.schema.yml
   @@ -0,0 +1,20 @@
   +  type: mapping
   

   Per https://www.drupal.org/docs/drupal-apis/configuration-api/configuration-... I think this should be configuration_object instead of mapping. On that section, at the end, it states:

   In all cases supported by core, the top level item in the .yml file will be a mapping with elements described in a mapping list underneath. You should use either of the two specific mapping subtypes config_object or config_entity.

2. +++ b/config/schema/ckeditor_media_embed.schema.yml
   @@ -0,0 +1,20 @@
   +    langcode:
   +      type: string
   +      label: 'Langcode'
   +    _core:
   +      type: _core_config_info
   +      label: 'Core config info'
   

Related to previous comment, langcode and _core are provided by the config_object.

3. Additionally, the third_party_settings property is not declared in this schema file.

   An example of what it would look like:

   third_party_settings:
     oembed_lazyload:
       oembed_lazyload_enabled: 1
       oembed_lazyload_providers:
         YouTube: YouTube
         Vimeo: 0
   

I've changed `plugins_installed_version` to `plugins_version_installed`, which is actually used.
Also I've fixed points 1 and 2 from previous comment, but I haven't found any third party settings, provided by this module.
I mean, that currently it provides only settings configuration, which needs schema. Please, correct me, if I'm wrong.