A new report suggests that Apple could release a nearly final build of OS X 10.9 to developers at WWDC.

AppleInsider
reader Tom noticed a Webkit bug report submitted through Apple's Radar
system that references an operating system build number of 13A451. The
first three characters of that number are believed to refer to OS X 10.9
and the last three characters are the internal build numbers.

Interestingly,
the last three digits are surprisingly high for an operating system
that has not yet been released. The final release of OS X 10.8 Mountain
Lion was released after only 269 builds. OS X 10.6 Snow Leopard was
released after 432 builds.

Major OS X releases usually have
higher build numbers. For example, OS X 10.5 reached build 581 and OS X
10.7 Lion reached build 511.

This could suggest that either
Apple is nearing a release for the operating system or that a critical
component is seeing a major update.

Last year, Apple released a developer preview
of its upcoming operating system in February; however, it did not do so
this year. It's possible that the company plans to unveil a nearly
finished version of the software at WWDC and have a much smaller test
window before its public release.

OS X 10.9 is reportedly codenamed 'Cabernet' and is said to introduce new 'power-user' enhancements
and borrow core iOS features. Major enhancements to Finder such as
tags and tabbed browsing modes, a new Safari web browser, and the
ability to keep different Spaces open on different monitors, is
expected.