Browsers. The update to macOS Catalina broke Firefox's ability to navigate links with the Tab key, but a fix is on its way; on the upside, the small floating thumbnail that shows up in the bottom-right corner whenever you take a screenshot (Cmd + Shift + 3) can now be dropped in a web page across all browsers / The Firefox UI is now built using Web Components by Brian Grinstead

JavaScript. Build your own React by Rodrigo Pombo

Creative Coding. Instanced line rendering by Rye Terrell / Fast and Free Music Separation with Deezer’s Machine Learning Library by Andy Baio

Performance. What to <link rel=dns-prefetch> and when to use preconnect by Daniel Aleksandersen