It would be great if there could be a dis-aggregated tab for just conversations.

ie convert the current conversation tab into timeline as is (keeps everything), and then create a conversation tab that only shows comments and reviews' comments (no labels, references from other issues, bases changing, force pushing, PR name changing, yada yada)

To

As it stands, when PRs get into the 50+ commits and more than a handful of comments and reviews, things become way to overwhelming to look through. Particularly when there is a comment you want to refer to (ie test/coverage info, etc), but gets collapsed away.

Great idea! This would be a huge quality-of-life improvement for long-running PRs! 🚀

I've been able to get some CSS that can help hide non-conversation bits in the timeline.
You can use stylus or something to toggle it, though some JS to turn it on/off would be nicer.

.js-timeline-item[data-gid^="ASEE_"],
.js-timeline-item[data-gid^="CRE_"],
.js-timeline-item[data-gid^="CTDE_"],
.js-timeline-item[data-gid^="C_"],
.js-timeline-item[data-gid^="DEE_"],
.js-timeline-item[data-gid^="DEME_"],
.js-timeline-item[data-gid^="HRFPE_"],
.js-timeline-item[data-gid^="LE_"],
.js-timeline-item[data-gid^="MIE_"],
.js-timeline-item[data-gid^="RDE_"],
.js-timeline-item[data-gid^="RFRE_"],
.js-timeline-item[data-gid^="RRE_"],
.js-timeline-item[data-gid^="RTE_"],
div[class="TimelineItem"]:not([data-view-component]) {display: none;}

Here's a bookmarklet to toggle the CSS on and off

hide:

javascript:(function(){var e=document.createElement('style');e.setAttribute("id", "timeline-css");e.innerText='.js-timeline-item[data-gid^="C_"], .js-timeline-item[data-gid^="CRE_"], .js-timeline-item[data-gid^="RFRE_"], .js-timeline-item[data-gid^="RRE_"], .js-timeline-item[data-gid^="CTDE_"], .js-timeline-item[data-gid^="HRFPE_"], .js-timeline-item[data-gid^="LE_"], .js-timeline-item[data-gid^="MIE_"], .js-timeline-item[data-gid^="DEE_"], .js-timeline-item[data-gid^="DEME_"], .js-timeline-item[data-gid^="ASEE_"], .js-timeline-item[data-gid^="RDE_"], .js-timeline-item[data-gid^="RTE_"], div[class="TimelineItem"]:not([data-view-component]) {display: none;}';document.head.appendChild(e)}());

show:

javascript:(function(){document.getElementById('timeline-css').remove()}());

That's amazing! 🎉 I've built a Chrome extension based on this design—you can check it out here! 🚀

Here's a bookmarklet to toggle the CSS on and off

I created a user script from this which can be used with Violentmonkey: https://greasyfork.org/en/scripts/582039-github-pr-hide-commits/code