Google autocomplete using your query history also reduces the information you learn from suggestions as you do the searching...

While in the past "indexDB.set undefined in " might autocomplete to show safari first, indicating a vendor-specific bug, it'll often now prefill with some noun from whatever you last searched (e.g. "main window") to "help" you.

Haven't found a way to disable that, annoying for understanding bugs, situations/context and root causes.