Income
Money coming in: the source it arrived from, the event you can file it against, and why none of the expense arithmetic applies to it.
What an income is
An income is money arriving. Like every transaction it carries an amount, a currency, a date and the wallet the money landed in.
It carries no lines. There is nothing to file it under the way spending is filed, so an income holds only that amount, a source and an optional event, and nothing more. The two currency figures that currencies describes, what arrived and what the wallet actually gained, both live on the transaction itself rather than on the income row.
Where it came from
What identifies an income beyond its amount is a source: the employer, the client, or the arrangement the money arrived from.
Sources are reusable, so the same one sits behind every payment from that arrangement rather than each one arriving unattached. Income sources covers creating them and what they gather.
Income against an event
An income can also name an event, the same way an expense line can. Money that belongs to a trip or an occasion is filed against it, and it counts toward what that event settles alongside the expenses filed there.
It is optional, and most income has no event attached to it.
Why it is always completed
An income is completed as soon as it exists. There are no lines to add up the way an expense's are, so none of the arithmetic statuses an expense can hold ever applies to an income.
The one thing that delays it is review. An income that came out of an import arrives as a draft, the same as any other imported row, and it stays one until you publish it. It is completed from that moment, not before.