Debugging docusaurus custom element issue

Component: Potentially docusaurus-theme-live-codeblock, possibly something else in the build system.

Ongoing discussion thread: facebook/docusaurus#5614

Source and demo sites

• ✅ docusaurus 2.0.0-beta.0: 2.0.0-beta.0 https://2-0-0-beta-0.dlpncn4sz6ns6.amplifyapp.com/
• ✅ docusaurus 2.0.0-beta.0 with minification: 2.0.0-beta.0-with-minify https://2-0-0-beta-0-with-minify.dlpncn4sz6ns6.amplifyapp.com/
• 🚫 docusaurus 2.0.0-beta.1: 2.0.0-beta.1 https://2-0-0-beta-1.dlpncn4sz6ns6.amplifyapp.com/
• 🚫 docusaurus 2.0.0-beta.1 with minification: 2.0.0-beta.1-with-minify https://2-0-0-beta-1-with-minify.dlpncn4sz6ns6.amplifyapp.com/
• 🚫 docusaurus 2.0.0-beta.6: 2.0.0-beta.6 https://2-0-0-beta-6.dlpncn4sz6ns6.amplifyapp.com/
• 🚫 docusaurus 2.0.0-beta.6 with minifications: 2.0.0-beta.6-with-minify https://2-0-0-beta-6-with-minify.dlpncn4sz6ns6.amplifyapp.com/
• 🚫 docusaurus canary canary: https://canary.dlpncn4sz6ns6.amplifyapp.com/
• 🚫 docusaurus canary with minification: canaary-with-minify https://canary-with-minify.dlpncn4sz6ns6.amplifyapp.com/

What

<o-embed>, a custom element written in lit element

Where

static/js/o-embed.bundled.js: rollup UMD output of @social-embed/wc

Loaded via docusaurus.config.js:

  scripts: ['/js/o-embed.bundled.js'],

index.js

<Playground className="language-html">{`<o-embed\n  url="https://youtu.be/FTQbiNvZqaY"\n  width="100%"\n></o-embed>`}</Playground>

What breaks

Live component on the front page in 2.0.0-beta 1 and up (front page)

What still works

Manual / normal JSX / MDX of <o-embed> in all versions