Answer
WAGECLASS and LEDGER are Application Context attributes just like Company — certain pages (HR-related ones especially) support setting one of these as an active context value, automatically scoping everything you do on that page to it without needing to add it to every search manually. Beyond that, a Configuration Context can be mapped to a specific Application Context value (for example, mapping one configuration context to wage class WA and another to WB), which lets different Page Configurations apply dynamically depending on which application context value is active when a context-aware page is opened.