This tool takes spending with no category and groups it by vendor, so you categorise a supplier once rather than categorising forty transactions from that supplier one at a time.
A suggested category comes with each group, based on the patterns already in your own books.
Why by vendor
Because that is how the decision actually works. You do not decide what a single fuel purchase was — you decide what purchases from that fuel supplier are, and then it is true for all of them, past and future.
Doing it transaction by transaction is the same decision made forty times, which is why most people abandon it half way and why a year of unsorted expenses is common.
Read the suggestion, do not trust it
The suggestion comes from your existing patterns, which means it inherits whatever you have done before, including the parts you got wrong.
It is reliably right on the obvious cases and worth a second look on the ones where a vendor does more than one kind of thing. A supplier you buy both materials and office equipment from cannot be categorised correctly by vendor alone, and those are the groups to split rather than accept.
The one to be careful with
Anything that looks like the owner's personal spending. It belongs out of business expense categories entirely, not filed into the nearest plausible one — it distorts every expense ratio it touches and it is the hardest thing to unpick later.
Why it matters more than it feels like it does
Uncategorised spending is not missing from your totals. It is missing from the breakdown — so a profit and loss shows the right amount left the business and cannot tell you what it bought.
That is the difference between knowing you spent too much and knowing where.
Afterwards
New transactions arrive continuously, so the review queue in Transactions is the ongoing version of this. This tool is for clearing the backlog; that screen is for not building another one.