Article: https://wordpress.org/documentation/article/site-editor/

Update for 6.3

General

• Change "Home" template name to "Blog home". 52048
• Site editor: only show view site link in view mode. 51279
• Update the bottom sticky section in the site editor details panel. 51274
• Disable block supports derived design tools when Blocking Editing Mode is not default. 50912
• Tweak edit site resizable frame handle. 50878
• Directly save if only changing current context. 50567
• Add view site link to site editor nav. 50420
• Update the document title in the site editor to open the command tool. 50369
• Add a command center to the site editor. 49330
• Add support for hiding breadcrumbs in the Site Editor 49518
• Hide navigation screen in site editor 49043
• Add descriptions to all panels in the Site Editor's dark side 48739
• Adds a global save button to the site editor. 47142)
• update the edit button. 48584
• Add back link to Design heading in site editor navigation to return to Dashboard. 47950
• Append template type and name to the site editor page title 47855
• Update the Save Button label when you're previewing a theme 51361
• Add Library for Template Parts & Patterns Management 51078

Patterns

• Rename Library to Patterns. 52102

Pages

• Add the pages menu to the site editor 50463
• Refer this PR for Content Editing in the Site Editor

Templates

• Add template actions in site editor navigation sidebar. 51054
• Update the add template menu. 50595
• Add a nested level when selecting templates or template parts 47777
• Append template type and name to the site editor page title 47855

Template Parts

• Sort template parts by type in navigation screen. 50841
• Add corresponding area icon to template part menu items. 52102
• Library: Rename template parts to library. 50769
• Add a nested level when selecting templates or template parts 47777

Styles

• Always show the Styles navigation item. 50573
• Add link to global styles revisions 51149
• Add Style Book 50566
• Styles section to the browse mode sidebar 49014
• Refer to this PR for details

Navigation

• Navigation in Browse Mode Refer to this PR

Command Palette

• Add a button to open it from the site editor view mode 50425
• Refer to this PR for more details

General

• Make sure all screenshots are relevant to the latest version
• Make sure videos, if any, are up to date
• Add ALT tags for the images
• Make sure the headings are in sentence case
• Convert all reusable blocks to a ‘regular block’.
• Update the changelog at the end of the article

Notes

1. Give an overview of the side bar in the Site Editor for Navigation, Styles, Pages, Templates, and Patterns. Navigation, Pages and Patterns will get a new page covering the details. Issues for the new pages will be linked to this issue.
2. We are not adding detailed updates for the Block settings - Typography, Color, Layout, Dimension and Border and for the More Options setting in the block toolbar. Pls mention the settings included for the block and link to the detailed settings pages instead.
3. Some of the PRs have great videos that can be added to the article.