https://trac.webkit.org/changeset/35050 added a site specific quirk for OpenCube QuickMenu,
which was used by NWA.com at the time, and erroneously detected any browser which returns
"4." in navigator.appVersion to be Netscape Navigator 4.x.
It has been 11 years since then, and NWA.com simply redirects to delta.com now.
Blink "removed" this site specific quirks in https://chromium.googlesource.com/chromium/src/+/dfa9e59a223802c69955a01d4c5f8fd8277c7fb2
The patch added a new implementation of navigator.appVersion to NavigatorID and made Navigator supplemented by NavigatorID but without ever removing Navigator::appVersion, which had the site specific quirk. Arguably, this was unintentional behavioral change by Chris.
The unused code in Navigator.cpp was subsequently removed in https://chromium.googlesource.com/chromium/src/+/70bb2b39ddf4d88ba048df2a67dd7de0780d7c28
The fact Blink/Chrome has been shopping a major browser engine for six years since the relevant code was removed is a good enough evidence that this workaround is no longer needed for Web compatibility.
Created attachment 364348 [details]
Committed r242779: <https://trac.webkit.org/changeset/242779>