However, since the product is not available for free, only our company and our current and future clients can be interested in technical questions about the framework and the plugin.
Although it might seem questionable to use a freely available public tool to answer an internal need that would otherwise cost money and time to install and maintain, I can't see anything in the FAQ that prevents us to do so. The only thing that might be considered "borderline" at first thought is that questions could be considered "too localized", but that would be a mistake: even if only a couple of dozens of users could be interested in the questions, they are very likely to stumble on any of the questions at some points, because they use the product and the framework a lot.
However, we don't want to exploit a loophole and abuse Stack Overflow, which we find very useful for all questions about very widely used technologies, so we prefer to be sure.
Q: Is it OK to use Stack Overflow to ask questions about a proprietary framework?