Have to disagree there... When it comes to password management, 1Password just doesn't fit the bill. They're source-viewable, but doesn't seem like you can do much with the available pieces of source code. And it's not self-hostable. Not saying everyone would want to, but the option, when it comes to passwords, is quite an important one. Not being open source as a password manager just means I *can't* even trust a third party with such things.
In the opposite end of the spectrum, Bitwarden has all the right ingredients down to reproducible builds.