It's been that way for the Service as far back as Archive.org has archived Adobe's general terms of service which was 2015-05-31. Here was the TOS then:
> 3.2 Licenses to Your Content in Order to Operate the Services. We require certain licenses from you to your content to operate and enable the Services. When you upload content to the Services, you grant us a non-exclusive, worldwide, royalty-free, sub-licensable, and transferrable license to use, reproduce, publicly display, distribute, modify (so as to better showcase your content, for example), publicly perform, and translate the content as needed in response to user driven actions (such as when you choose to store privately or share your content with others). This license is only for the purpose of operating or improving the Services.
They changed from "Services" to "Services and Software" in June of 2018:
> 4.3 Licenses to Your Content in Order to Operate the Services and Software. We require certain licenses from you to your Content in order to operate and enable the Services and Software. When you upload Content to the Services and Software, you grant us a nonexclusive, worldwide, royalty-free, sublicensable, and transferable license to use, reproduce, publicly display, distribute, modify (so as to better showcase your Content, for example), publicly perform, and translate the Content as needed in response to user driven actions (such as when you choose to privately store or share your Content with others). This license is only for the purpose of operating or improving the Services and Software.