The only timeframe we found
It belongs to one ingredient, and it is about safety
NIH gives green coffee bean extract a sentence with two numbers in it: “Green coffee bean extract seems to be safe (at up to 200 mg a day for 12 weeks).” A course length and a daily amount, together in one line, which is exactly the shape a useful instruction takes.
It is also the only one. No other ingredient on this label carries a course length in any source we opened, and this bottle publishes no amount for green coffee bean extract, so the sentence has nothing here to attach itself to.
Notice what kind of sentence it is as well. It describes how long the ingredient has been looked at for safety, not how long somebody took it before anything happened. Those are different questions, and a page that blurred them would be turning a safety window into a promise of results.
The caffeine numbers are daily ceilings rather than course lengths. FDA cites “400 milligrams a day - that's about two to three 12-fluid-ounce cups of coffee - as an amount not generally associated with negative effects”. At the other end of the same page: “The FDA estimates toxic effects, like seizures, can be observed with rapid consumption of around 1,200 milligrams of caffeine”. Both are per-day figures, and both need a milligram figure on the bottle to be worth anything to a reader. Three of the five named ingredients contain caffeine - caffeine anhydrous, green coffee bean extract and green tea extract - and no caffeine figure is printed for any of them, or for the serving as a whole.