Some variations are flavoured with lime.
Garlic Salt is used as a seaoning in cooking to add a pronounced garlic flavour; it is almost never used at the table.
To make your own, mix up to 1 part garlic powder with 3 parts regular table salt. Shake to mix. Or, make “fresh garlic” salt, mash 1 peeled garlic clove with 1 teaspoon of regular table salt.
For every clove of fresh garlic in a recipe, you can use 1/2 teaspoon of garlic salt. Hold back on any other salt in the recipe, then add only what plain salt you think is necessary for taste afterward.
OR just use fresh garlic and regular salt in quantities to taste.