The whole existence of Proton revolves around a trustworthy, easy-to-use suite of end-to-end encrypted applications. But one thing is to use Proton's digitally signed mobile applications, another is to use Proton's web-based applications.

So I suggest the early adoption of WEBCAT, a Freedom of the Press Foundation project currently in alpha.

From their website (https://webcat.tech/):

"""
The Problem

Websites can change their code at any time, and HTTPS alone does not guarantee that every user receives the same, intended web application. WEBCAT addresses this by enabling signed delivery and transparency log–backed distribution of participating web applications, allowing end users to verify exactly what they received from a website.
"""

WEBCAT's developers are currently, as of March 2026, asking for developers and webmasters to join the alpha tests.

From the alpha announcement (https://securedrop.org/news/webcat-alpha/):

"""
We especially want feedback from teams who want to use WEBCAT, but find that the set of web application features supported by WEBCAT are not sufficient for their use case. WEBCAT has already expanded the features it supports in response to such feedback, and we want to continue doing so.
"""