Steps to reproduce:
In the tab bar there's some sort of sub-pixel misalignment in the type on fonts that makes them alternately blurry and sharp depending on the position.
all elements positioned at 1x resolution rather than hidpi resolution, sharp fonts.
Orion, OS version; hardware type:
Version 0.99.119-beta (WebKit 615.1.1)
MacOS 10.14.6 Mojave
using 1080p dell monitor
(note: in Safari, you can see a subtler but similar effect when moving a tab how I am here, but when at its final position the type is always sharp)