I got a weird header from my local Apache 2.2.4 today.
X-Pad: avoid browser bug
These guys could tell me what it was:
In six cases the HTTP message “X-Pad: avoid browser bug” was sent. This was an unannounced change to Apache version 1.2b9 which provided a fix for a bug in Netscape versions 2.x, 3.x and 4.0b2.