What, for that matter, is The Bug Directory? Is it the Sourceforge "Bugs browser" specific to Tcl [L1 ] ? If so, then for example, to read up on Bug 219191, means to retrieve http://sourceforge.net/tracker/index.php?func=detail&aid=219191&group_id=10894&atid=110894 . But why are some Bugs in the range above 600000? Where are the reports for Tk, tcllib, and so on?
If one just wants results, rather than the technical details, Don Porter's "SourceForge bug-reporting interface" is convenient. Also pertinent: "How do I report a bug in Tcl, Tk, ...".
DKF: Bug numbers are colossal because SourceForge uses a single bug numbering system for all issues reported on SF's trackers across all projects. Their site, their tracker code, their rules, no big deal.