Since I've been asked for the current state of per-domain various times, here's a quick overview:

History I've planned to implement this as part of the recent crowdfunding, but things have taken a bit longer than expected there (and I like doing things properly rather than doing more but half-baked). See these two blog posts (especially the last sections) for more context. Because of that, I haven't been able to work on this full-time like I originally wanted.

Current status There's some thoughts on how this affects various parts of qutebrowser, but there's no code yet. However, the requirements to get started on this (the new config) are finally out of the way, even though it took almost three years because I was mostly busy with tests and QtWebEngine stuff before starting work on the new config.

What I'm busy with Currently, there's a couple things keeping me busy: My studies (and other real-life stuff). This will always have priority over qutebrowser work, and the workload is a lot bigger than I anticipated, as there's a lot of project work I need to do during the semester (something like 13 projects, compared to 2 or so last semester) to be allowed for the exams.

Taking care of the T-Shirts and other rewards (other than stickers) for the crowdfunding. I postponed this during the full-time work so I could finish the new config, but this takes a lot more time than one might imagine.

Taking care of contributions - a lot of nice contributions (such as GreaseMonkey support) are currently in the pipeline, but taking care of reviewing those and "mentoring" people also takes a fair amount of time.

"Support" - meaning everything related to helping in people in the IRC channel, Reddit, private mails, issues on GitHub, etc. It might not seem like much, but it's easily an hour or so per week as well. It's not something I want to do less off though, as I think it's very important (and it's also a nice break from all the coding and writing I'm doing for my studies). In the time remaining for qutebrowser work after that, I really don't have the time nor mental energy to work on something big like this I'm afraid. If I push code changes to qutebrowser myself lately, it's either some important bug fixes, or just something I felt like would be fun for once again.