Change description to remove specific mention of up/down arrow keys and clarify it to make the specific characteristics of spinbuttons more clear. Proposed text follows.
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A widget that allows users to choose a value from a set, or range, of discrete values. For example, select a number from 1 to 59 for the minute of an hour when setting an alarm.

A spin button provides ways to easily increment and decrement the value. If the range is large, it may support changing the value by both a single step and by multiple steps at once. For instance, in the alarm example, the user may be able to move by 1 minute with the arrow keys and by 6 minutes with PageUp and PageDown.

A spinbutton usually includes a text field that displays the current value and allows users to directly edit it.

Question: should it include something like the following?
It may also support commands for moving to the minimum and maximum value. And, the button "spins" around so that incrementing from the maximum value will set it to the minimum value and decrementing from the minimum value will set it to the maximum value.