I've recently noticed that Chrome will sometimes predict and offer autocomplete suggestions for search results (as opposed to previously visited sites or bookmarked sites) in the omnibox while it is in Incognito mode/Guest window. For example opening a Guest Window and typing "dr w" into the address bar suggests the following searches:
Why/how is this happening?
Since Chrome 76 there is an experimental offline prediction model that allows it to create search suggestions locally. In Chrome 87 if I go to chrome://flags/ and search for "incognito" the following experiment is found:
Omnibox on device head suggestions (incognito only)
Google head non personalized search suggestions provided by a compact on device model for incognito
The rationale is that the model reduces the time it takes for suggestions to appear (which is useful in poor network environments). Predictions that come from the local model don't appear to send anything over the network which would explain why it can be used in incognito-style environments (as predictions are not leaking the partial searches). It's not 100% clear but it looks like the model may actually be shipped within Chrome itself but it can also be downloaded and updated.
