Apple late in the night released an updated build of Mac OS X 10.6, 10A286, to registered ADC developers. According to an Ars reader familiar with the test build, the shrinking list of known issues is a good sign that the OS is "getting polished up."

Our source indicated that the new items in the build include a revised QuickTime Player, which has a "minimal UI" that is more suited to a better playback experience. More of the Finder has gotten a Cocoa makeover, including the Desktop, Get Info window, and Contextual Menus. And the current Safari 4 beta has replaced the previous Safari 4 developer preview as the default browser.

If these features—along with the major architectural improvements going on underneath the surface—have you interested, AppleInsider reports that text handling in Snow Leopard will also receive some major productivity enhancements. As an example of a feature moving from iPhone OS to Mac OS proper, Snow Leopard will gain an automatic typing correction feature. Unlike the iPhone implementation, which gives the user an option to ignore the correction, the version in Mac OS X would just correct common misspellings as soon as the spacebar is hit (without the pop-up bubble to cancel it).

In addition, Snow Leopard will have an OS-wide ability to use what Apple is calling "Substitutions." Like the "replace text as you type" ability in Microsoft Word, or at least some of the functionality of programs like Text Expander, typing "(c)" for instance, will be replaced with a proper � glyph. In a slightly less trivial example, "IL" could be replaced with "Infinite Loop," or whatever a user chooses.

AppleInsider's sources say some substitutions are already defined in the latest developer build, and these substitutions can be individually activated or deactivated, along with any user-defined additions. These simple substitutions won't replace the advanced functionality of stand-alone apps, but for many it will be a nice convenience.

Finally, the update to Mac OS X will see more system-wide integration of Services and Data Detectors. Services are small bits of functionality that can be applied to a selection of text and accessed via the Application menu. However, Snow Leopard will add access to some services directly in a contextual menu of a selection. And Data Detectors, which currently work in Mail to automatically identify contact information or dates, will work in any application that uses Mac OS X's Core Text engine.

The last test build of Snow Leopard was released to developers just a month ago. Based on statements made as last year's WWDC, Snow Leopard should be released sometime this June.