[DOCS] More cleanup in developer docs (#90506) (#90636)

Author: lcawl

docs/developer/contributing/development-ci-metrics.asciidoc

@@ -44,15 +44,9 @@ All metrics are collected from the `tar.gz` archive produced for the linux platf
 [[ci-metric-distributable-file-count]] `distributable file count` ::
 The number of files included in the default distributable.
 
-[[ci-metric-oss-distributable-file-count]] `oss distributable file count` ::
-The number of files included in the OSS distributable.
-
 [[ci-metric-distributable-size]] `distributable size` ::
 The size, in bytes, of the default distributable. _(not reported on PRs)_
 
-[[ci-metric-oss-distributable-size]] `oss distributable size` ::
-The size, in bytes, of the OSS distributable. _(not reported on PRs)_
-
 
 [[ci-metric-types-saved-object-field-counts]]
 ==== Saved Object field counts

docs/developer/getting-started/development-plugin-resources.asciidoc

@@ -14,8 +14,8 @@ You can use the <<automatic-plugin-generator>> to get a basic structure for a ne
 {kib} repo should be developed inside the `plugins` folder.  If you are building a new plugin to check in to the {kib} repo,
 you will choose between a few locations:
 
- - {kib-repo}tree/{branch}/x-pack/plugins[x-pack/plugins] for commercially licensed plugins
- - {kib-repo}tree/{branch}/src/plugins[src/plugins] for open source licensed plugins
+ - {kib-repo}tree/{branch}/x-pack/plugins[x-pack/plugins] for plugins related to subscription features
+ - {kib-repo}tree/{branch}/src/plugins[src/plugins] for plugins related to free features
  - {kib-repo}tree/{branch}/examples[examples] for developer example plugins (these will not be included in the distributables)
 
 [discrete]

src/core/CONVENTIONS.md

@@ -19,10 +19,7 @@ Definition of done for a feature:
 - has been verified manually by at least one reviewer
 - can be used by first & third party plugins
 - there is no contradiction between client and server API
-- works for OSS version
-   - works with and without a `server.basePath` configured
-   - cannot crash the Kibana server when it fails
-- works for the commercial version with a license
+- works with the subscription features
    - for a logged-in user
    - for anonymous user
    - compatible with Spaces