Proton Mail: Better Search Idea - make a private searchable database of an individual's entire email account that is synced across devices. Works like it does on a desktop web session when one allows indexing of message content, but instead of keeping the index file only in the local browser's cache, it is encrypted and sent back to the email account on Proton's server (or possibly sync to Proton Drive). Any new mail session that successfully logs in to the account (desktop, mobile, web) will download the database, decrypt, index and add just the new messages, use database for the current session but also re-encrypt and sync to account. This will keep resource demands at a minimum across platforms, especially for mobile devices.