A more thorough explanation:

An enabling source is a document that prevents an invention from being patented because it provides enough information for someone skilled in the field to create the invention before the patent application is filed. This is known as the enablement requirement.

For example, if someone invents a new type of car engine and publishes a detailed article explaining how it works, someone else could use that information to create the same engine before the inventor files a patent application. In this case, the article would be considered an enabling source and the inventor would not be able to obtain a patent for their invention.

Another example could be a scientific paper that describes a new drug and its chemical composition. If the paper provides enough information for someone to create the drug before the inventor files a patent application, the paper would be considered an enabling source and the inventor would not be able to obtain a patent for their invention.