PwSafe (https://pwsafe.org)

The format is completely open and there are many implementations and apps. I have used the file (in that format) for at least 20 years. I've gone through different apps as they come and go. I sync the data file between all my systems/devices using a Nextcloud server.

My current main apps are Password Gorilla (on Linux - also works on Windows), Strongbox on iPhone, and PasswdSafe on Android-based devices (such as /e/).