According to Robert C. Martin in the Clean Architecture book:

«Historically, the SP has been described this way:

A module should have one, and only one, reason to

change. […] about. Indeed, we can rephrase the principle to say this: A module should be responsible to one, and only one, user or stakeholder. […] Thus the final version of the SRP is: A module should be responsible to one, and only one, actor.»