The extension uses an SQLite database in the Origin Private File System[0]. Disabling the extension keeps the database, while removing it deletes the database.
Regarding performance, here is how it works: the extension accumulates page changes (thanks to a Mutation Observer[1], so I do not have to regularly read and compare the page) for some time, then checks if the sentences are in the database. Only unknown sentences are converted to embeddings.
The extension is CPU-only currently (WebGPU support was not merged yet in transformers.js), so it may be slow. I understand your concern, while that is a proof of concept, I consider a good performance to be vital to a good user experience.
Regarding performance, here is how it works: the extension accumulates page changes (thanks to a Mutation Observer[1], so I do not have to regularly read and compare the page) for some time, then checks if the sentences are in the database. Only unknown sentences are converted to embeddings.
The extension is CPU-only currently (WebGPU support was not merged yet in transformers.js), so it may be slow. I understand your concern, while that is a proof of concept, I consider a good performance to be vital to a good user experience.
[0] https://developer.chrome.com/blog/sqlite-wasm-in-the-browser... [1] https://developer.mozilla.org/en-US/docs/Web/API/MutationObs...