Activity «While …» can be found in section «Basic.Loops».

Cycle is a type of action assuming repeatable task within algorithm.
Cycle until... - such type of cycle will be reiterated until the certain condition is satisfied. For example, until there are certain files within the filder or there are unread email messages left etc.
The cycle will be repeated until the condition is satisfied/not satisfied according to settings.
Нажмите на изображение, чтобы увеличить его.