The Wikipedia page has been modified since the question was posed and the cited text disappeared, which is a good thing as it does not make much sense. Now it can be interesting to note that the preceding sentence was

Action is a general physical concept related to dynamics and is most easily recognized in the form of angular momentum.

So I take it that the original wiki editor had in mind the path integral formulation where the action (a quantity with the same units as angular momentum, and the Planck constant) is responsible for the phase relationship between alternate paths and thus governs their interference.

From this perspective the action could maybe be argued to represent the essence of quantum mechanics. But it would be very misleading to formulate this idea by confusing action and angular momentum; see this post for a related discussion.

The Wikipedia page has been modified since the question was posed and the cited text disappeared, which is a good thing as it does not make much sense. Now it can be interesting to note that the preceding sentence was

Action is a general physical concept related to dynamics and is most easily recognized in the form of angular momentum.

So I take it that the original wiki editor had in mind the path integral formulation where the action (a quantity with the same units as angular momentum, and the Planck constant) is responsible for the phase relationship between alternate paths and thus governs their interference.

From this perspective the action could maybe be argued to represent the essence of quantum mechanics. But it would be very misleading to formulate this idea by confusing action and angular momentum; see this post for a related discussion.