The Backstory
The publish queue is a commonly used but rarely understood feature of the Sitecore platform. What's more, this fundamental feature can occasionally cause problems when publishing content - hence we most publishing workflows and item-level publishing rely on the more comprehensive Smart Publishing.
In short, the publish queue stores a list of items that have been created, updated, or otherwise modified in the master databases since the last publish and are in a final workflow state that would justify an update in the web database. An Incremental Publish uses the publish queue to push out those changes. This is Sitecore's way of speeding up publishing for smaller changes.
Unfortunately bad things do happen, and sometimes the publish queue becomes unreliable and is cleared prematurely. Sometimes developers might want to see what's in the publish queue for debugging purposes. Sitecore provides no built-in way to see the actual contents of the publish queue without writing backend code.
The Solution
My existing module (Sitecore Publish Reporting Kit) provides detailed reporting of the publish queue, but it also does a bunch of other stuff related to publish logging. Wouldn't it be nice to have a single-file, drop-in solution for viewing just the Sitecore publish queue?
If you just want to see the publish queue without the weight of installing a module, I've built a custom Sitecore admin page that does just that:
Hit up the GitHub link below, download the ASPX page, and drop it in your /sitecore/admin folder to get started.
Download and source: GitHub: Sitecore Publish Queue Detail