A few Google engineers are rewriting scratch-blocks to use modern Blockly. This will likely break a significant number of editor addons, as -blocks is a very old, and quite modified, fork. Below are instructions for building this rewrite locally for testing addons/extension.

Modern blockly scratch-blocks setup

git clone https://github.com/scratchfoundation/scratch-editor.git --branch spork --depth=1 # Git history is large
cd scratch-editor/
npm ci
npm run build

Once setup run npm run start in scratch-editor/packages/scratch-gui to start it on localhost:8601.

Compatibility checklist

Enabled by default

• editor-devtools
• find-bar
• middle-click-popup
• jump-to-def
• place-backpack-code-at-cursor
• editor-cleanup-plus

Recommended

• editor-number-arrow-keys
• hide-flyout
• fix-editor-comments
• editor-searchable-dropdowns
• block-switching
• data-category-tweaks-v2
• fix-pasted-scripts (Does nothing, editor doesn't stick pasted scripts to mouse)
• reorder-custom-inputs
• color-picker
• folders

Featured

• zebra-striping
• load-extensions
• custom-zoom
• debugger
• block-duplicate
• editor-comment-previews
• block-cherry-picking (Included in vanilla)
• hide-new-variables
• name-backpack-items (Trying to put any script into the backpack on new Blockly currently crashes Scratch, even with SA disabled)
• rename-broadcasts
• editor-stepping
• blocks2image
• script-snap
• swap-local-global
• variable-manager

Others

• number-pad
• transparent-orphans
• copy-reporter
• ctrl-click-run-scripts
• no-script-bumping
• editor-sounds
• editor-extra-keys
• editor-random-direction-block
• hide-backpack

Themes

• block-palette-icons
• cat-blocks
• editor-colored-context-menus
• editor-compact
• editor-theme3
• custom-block-shape
• custom-block-text
• editor-stage-left
• editor-dark-mode
• columns
• workspace-dots
• editor-square-inputs