If there is a brewing stand that is empty or contains only glass bottles, shift clicking a single glass bottle will stack them in the brewing stand. This can be repeated to get stacks of 64 glass bottles in each slot.
I believe this to be unintended as simply clicking and moving a stack or shift clicking a stack results in only one glass bottle being moved, so this seems to be a harmless yet unintended bug.
Stacking the bottles in this way seems to give accurate comparator outputs, and even more so, is able to produce all signal strengths 0-15 that a brewing stand otherwise wouldn't be able to. This could be considered useful in some redstone projects, though none specifically come to mind
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We're tracking this issue in MC-114462, so this ticket is being resolved and linked as a duplicate.
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