Issue #883038 by pillarsdotnet, ShutterFreak, anarcat: ereg() and ereg_replace() are deprecated but Drupal 6 will not migrate to preg to avoid breaking APIs, so we need to silence the warnings coming out of the use of ereg on PHP 5.3+

Issue #1169034 by mfb: fix notice in file_create_filename() for cases when the ext variable did not exist previously

Issue #163445 by webengr, mlsamuelson, greg.1.anderson, pescetti: fix issues with IE not being able to download private files served over SSL with additional headers

Issue #690358 by sbrattla, jhodgdon, nenne: overhaul file_check_directory() documentation due to various issues

#370958 by Rob Loach, drewish, c960657, neilnz: some Adobe Flash MIME types were missing from our MIME listing

#360605 by Berdir et al.: make Drupal core work with PHP 5.3.0 out of the box (fixes for incompatibilities introduced with PHP 5.3.0)

#197266 by ufku, lilou, Dave Reid, c960657, drewish: Save a query by only calling file_space_used() when a limit is provided.

#20527 by mpare, bdragon, mfb: file_transfer() should only call ob_end_clean() if there was an actual output buffer opened

#210219 by htalvitie, yched: initialize block caching properties properly on install (and update bugos RC2 sites as well)

- Patch #199955 by saxofaan: file_upload_max_size() returns results in bytes, not in mega bytes.

#194369 by lots of contributors: move default files directory to sites/default/files which can be created automatically on install, so no need to bug the user about it, making the install process easier

- Patch #163246 by keith smith, freso, O Govinda, catch, webchick et al: fixed minor spelling issues and fixed spacing issues.

#173664 by fractile81: fix order of precedence in file_scan_directory(), so subtheme files will really override parent theme files

#172943 by drewish: fix file_save_upload() conformance to its API documentation by treating the 'dest' param as a directory. Also fixes #176876 so temporary files are properly stored in the temp directory.

#180126 by mmoreno, drewish and scor: add realpath() call to file_save_data(), so Windows will create temporary files properly

Four watchdog() calls which still used t(), identified by myself after implementing extraction code for Drupal 6 at #182765