Hey @rafuru,
I have just given it a quick go and it appears to work how @marcus has suggested. On my Docker host I have created /home/docker/nodes/ and in there I ran…
git clone https://github.com/hckdotng/n8n-nodes-puppeteer-extended.git
cd n8n-nodes-puppeteer-extended/
npm i
npm run build
With the node now built I have then set up a volume in my container so that I can access /home/docker/nodes/ from /custom-nodes I have then set N8N_CUSTOM_EXTENSIONS=/custom-nodes/n8n-nodes-puppeteer-extended/dist/nodes/Puppeteer, Started my container up and I can see the below.
As another test I have deleted that attempt and just ran npm install n8n-nodes-puppeteer-extended then set N8N_CUSTOM_EXTENSIONS=/custom-nodes/ and that has also worked.
Can you share the steps you followed?