Those of you who own Glock pistols know that it takes a bit of know-how or work to open a Glock magazine for cleaning, or for adding a magazine extension to increase round capacity. The reason why Glock chose this method of retaining is to prevent accidental release of the magazine springs and cartridges in case they are dropped. The military and law enforcement agencies appreciate this system more than the average Joe.
Some Glock owners in fact dread removing the bottom retainer, since the retainer is held by two tabs under spring pressure. Various tools are sold for this purpose, but common tools can be used, which can incidentally damage the plastic housing if not done right. Some brute methods can indeed destroy the tabs on the side.
The best solution I have found is a good multi-purpose tool made by Knippex of Germany which I have found to be superior to anything I have tried. It is a self-ratcheting wrench which can be used to apply the right amount of pressure without marring the plastic housing of the magazine. It really works good, albeit an expensive tool ($57 for the 7.25 inch at Chadstool Box below.) However, this tool can be used for many other things around the house or car, unlike the expensive tools sold exclusively for this, which don’t work as good as this tool. This tool is good for both .380 and all 9mm Glock magazines, and may work just as well on other brands.
https://chadstoolbox.com/86-plier-wrench/
