Google has been caught testing features that do not work in Chrome 74, but work in Chrome 75. Chrome 75 is not out yet in production for the public, it is being testing in beta right now. Valentin Pletzer caught Google testing Chrome 75 features yesterday. Martin Splitt from Google said this is to be expected in order to keep GoogleBot evergreen going forward.
Martin from Google said "Keep in mind that in order to keep Googlebot evergreen we continuously test new versions on small sets of URLs." That makes sense.
Here is what Valentin found the other day and posted on Twitter:
Valetine also noticed some fun with the user agent here:
also notable: The useragent shown in the http-request is different to the one returned by navigator.userAgent pic.twitter.com/6xCcb9WYrj
— Valentin Pletzer (@VorticonCmdr) May 19, 2019
As Detlev Johnson said, Google just added this to the beta version of Chrome 75:
They added it to V8 a few days ago. Evergreen! https://t.co/BjJ3QHN9rI
— s/ᛑᛂᛐᛛᛂᚡ/𝔡𝔢𝔱𝔩𝔢𝔣/ 🦆🌲⛷🏔🛰 (@deckarts) May 19, 2019
Here is how Martin from Google explained it:
Keep in mind that in order to keep Googlebot evergreen we continously test new versions on small sets of URLs.
— Martin Splitt @ 🇨🇭🏡 (@g33konaut) May 19, 2019
So this is really good news and shows Google is on the right path to continue to ensure GoogleBot is evergreen.
Forum discussion at Twitter.