While I suspect that many of the majors, like Pizza Hut, Papa John's, Domino's and Little Caesars, would prefer not to disclose the ingredients they use in their doughs and sauces, for competitive and other reasons, they will do so on occasion. Sometimes they will unilaterally post the information on their website, and sometimes it will be provided to individuals on request. I once called Papa John's to request this type of information, which I received via email, and member Wazatron did this recently with Donatos via email. The companies often get requests for information on ingredients from vegans, people with allergies and nutritionists, so they are used to this and there is a public interest to be served. I have even found ingredients listings for pizza products in online public documents by which companies are required to disclose the information as a prerequisite to doing business with schools (usually for school lunch programs) and similar organizations. So, even though their dough formulations are more likely to be proprietary (and usually produced to their specs), it is hard for the majors to preserve much secrecy in their ingredients listings for the reasons mentioned above.
Having worked on several pizza dough reverse engineering projects, I can say that just having the ingredients list takes you only so far. While the ingredients are rank ordered by weight, that doesn't tell you actual percents. Sometimes you can't even tell what kind of flour is used. Typically, the flour is described very broadly and generically, such as "wheat flour". It takes a lot of work and knowledge about doughs and pizza styles in general to be able to successfully reverse engineer a dough (or sauce) just from an ingredients list. Of course, having the actual product, such as the one mentioned by DNA Dan, makes the task a great deal easier. Then it becomes a matter of trying to replicate the finished product in the home. That isn't always easy either.