I recommend that the developer documentation relate to the current version of WordPress Core. As it stands, the current version relates to the Gutenberg plugin, which is not always in use. (Confirmed by @t-hamano in @WordPress/outreach.)

What problem does this address?

Some of the documentation—e.g. https://developer.wordpress.org/block-editor/reference-guides/slotfills/plugin-document-setting-panel/—is for the code in the Gutenberg plugin, not in WordPress Core.

What is your proposed solution?

The documentation should refer to the current version of core, not of the plugin.