Avoid repeated use of “existing”

Given that the final sentence of this mission statement contains just 28
words, having the word “existing” occur in it 3 times seems like maybe a
couple times too much…

main.jsx

@@ -18,9 +18,9 @@ function Home() {
  collaborate on API interoperability. We focus on documenting and
  improving interoperability of web platform APIs across runtimes
  (especially non-browser ones). This is done through discussions among
- runtimes, proposals for new and existing web APIs in existing
- specification venues (WHATWG, W3C), and documentation of existing
- runtime behaviours.{" "}
+ runtimes, proposals in specification venues (WHATWG, W3C) for new
+ web APIs and for changes to current web APIs, and documentation of
+ existing runtime behaviours.{" "}
  <a
  href="/faq"
  class="text-pink-500 hover:text-pink-700 hover:underline"