In this Composer tutorial learn about the differences between all these characters:
Depending on your dependency manager you can define version constraints using wildcards (*), comparators like =0.9.0,=4.1.3,=4.1.0,=0.4.0,=4.0.0,=4.1.3,=4.1.0,=0.4.0,=4.0.0,
A little easier to remember than the php date format however this isn’t even all the options. The docs say you can also use a range and a hyphen range.
