There's a chance it's using Tauri (rust) https://tauri.studio/en/ if it's truly not using Electron but a similar concept. However WASM builds in Electron would make more sense if they use the term Electron.
yeah I'm aware it contains chrome, I mentioned that much of the functionality has been moved out and is actually implemented in rust, this is verifiable simply by running `1password --log trace`
EDIT:
168MiB resident memory on my system (just checked).
Though it malloc'd (but never used) 32G, that's worrying.
Link below to the behind-the-scenes article. I have no experience using the Linux app so I'm not sure of the performance but a lot of the core seems to be written in Rust compiled to WASM which is the way it's now being done for their browser extension. Personally everyone keeps cribbing about electron but I hope 1Password has found a way to make good on performance