Two Learning Center performance pages 404 with no redirect (brotli-vs-gzip, TTFB glossary)

### Existing documentation URL(s)

The two broken pages — note these are `www.cloudflare.com/learning`, not `developers.cloudflare.com`. See "Additional information" below.

- https://www.cloudflare.com/learning/performance/brotli-vs-gzip/
- https://www.cloudflare.com/learning/performance/glossary/time-to-first-byte-ttfb/

Suggested redirect targets, all currently live on the developer docs:

- https://developers.cloudflare.com/speed/optimization/content/compression/
- https://developers.cloudflare.com/rules/compression-rules/
- https://developers.cloudflare.com/glossary/
- https://developers.cloudflare.com/speed/troubleshooting/slow-website/

### What changes are you suggesting?

Both of these Learning Center URLs return **404 with no redirect**:

- `https://www.cloudflare.com/learning/performance/brotli-vs-gzip/`
- `https://www.cloudflare.com/learning/performance/glossary/time-to-first-byte-ttfb/`

Neither appears in `https://www.cloudflare.com/sitemap.xml`, which currently lists 33 URLs under `/learning/performance/`. So the content looks removed rather than moved.

Both URLs are still widely linked from outside Cloudflare, and both are the kind of page someone lands on mid-investigation — "should I use Brotli or gzip" and "what counts as a good TTFB" are among the most common questions people arrive with.

**Suggested fix:** 301s to the live equivalents, which are all on the developer docs now. That would repair the dead links without needing the Learning Center articles rewritten.

| Dead URL | Suggested target |
|---|---|
| `/learning/performance/brotli-vs-gzip/` | `https://developers.cloudflare.com/speed/optimization/content/compression/` — covers the per-plan default algorithm; `https://developers.cloudflare.com/rules/compression-rules/` covers choosing the Brotli/gzip/Zstandard order |
| `/learning/performance/glossary/time-to-first-byte-ttfb/` | the "time to first byte (TTFB)" entry at `https://developers.cloudflare.com/glossary/`, or `https://developers.cloudflare.com/speed/troubleshooting/slow-website/` for the TTFB target table |

If restoring or rewriting the Learning Center articles is preferred over redirecting, that works too — the main thing is that neither URL currently resolves to anything.

### Additional information

**On filing this here:** I couldn't find any feedback route for `www.cloudflare.com/learning`. Those pages carry no "Was this helpful?" control, no edit link and no report link, and the footer offers only Contact sales / Support / Report abuse / Report a security issue. I understand this repo covers `developers.cloudflare.com` only — if there's a better home for Learning Center content bugs, please point me at it and I'll move this. If there isn't one, that might itself be worth fixing.

**Minor, while I'm here:** `https://www.cloudflare.com/learning/cdn/what-is-caching/` says "335+ PoPs", while `https://developers.cloudflare.com/reference-architecture/architectures/cdn/` says "hundreds of cities worldwide" alongside 405 Tbps and "95% of the world's Internet-connected population within 50 ms". Not a contradiction, but the Learning Center figure is both more precise and probably staler, and the two read oddly side by side.