1. CSS class naming – bloated, hard‑to‑read names vs. short hashes
Many commenters criticize GitHub’s long generated class names (e.g., DirectoryContent-module__Box_3__gl6dE) for inflating CSS size and hurting performance, and advocate shorter hash‑based names for better gzip/brotli compression.
“Currently, the production build is using long‑dev class names. e.g.
DirectoryContent-module__Box_3__gl6dEcould be compiled to a shorter hash likegl6DE3a2.” – efortis
“The only thing hashing classes achieves is making it difficult for users to use ad blockers and/or custom CSS.” – notpushkin
“The improvement would be shipping human‑readable structure to allow easier user overrides, not that hash abomination.” – eviks
2. Whether performance optimizations are worth the cost at scale
A recurring debate centers on measuring performance, the excuses teams make, and the point of diminishing returns when a codebase is large.
“Performance is not complicated. You measure something and compare the numbers…. The shitty team excuse…. Throwing performance data away and lying about it…. Guessing.” – austin‑cheney
“You measure and improve the metric, but at what cost, when should you stop? Have you worked on a 1 M+ LOC web app?” – karolusrex
“Isn’t this backwards? Optimizing assets becomes more important with scale, not less.” – jchw
“No, we’re asking for it to be taken seriously by the organisation… Their work is ‘subjective’ improvements but often it’s just building tooling.” – maccard
3. Organizational and practical constraints – legacy, design systems, and refactor feasibility
Defenders point out that large, modularized codebases have real constraints (design systems, legacy code, chunking) that make sweeping CSS rewrites non‑trivial, though incremental approaches or tooling (functional CSS, LLMs) can help.
“These type of comments often come from a place of arm‑chair reasoning where you might not sit on the experience of working hands‑on in a large team on a large product…. Maintaining a design system, working with scoped classes, legacy code, and dealing with the complexities of chunking…” – karolusrex
“The beauty of functional CSS is that you can progressively transform everything. GitHub runs on an entire modularized codebase, they can clean up the entire codebase within weeks, days if they use agents…” – meerita
“With modern LLMs you can vendor the design system around and cut it to the bone on every app. If your organization ships a worse solution than Claude slop, do you really want to stick with it?” – blfr
“You can have both [CSS‑in‑JS and CSS modules] while also not shipping any JS runtime for CSS in JS!” – lloydatkinson (referencing vanilla‑extract).