Generally you should know that TYPO3 generates temporary “cached” scripts in typo3conf/. Those would look like these:

-rw-r--r--    1 httpd    httpd       27501 Jan 29 18:35 temp_CACHED_ps2d95_ext_localconf.php

-rw-r--r--    1 httpd    httpd       83513 Jan 29 18:35 temp_CACHED_ps2d95_ext_tables.php

You can experience more than these files. In that case it will be because of multiple paths, symlinks or just old files.

You can at any time remove these files and on the next hit to the system they will be re-written. These files simply contains all ext_tables.php and ext_localconf.php files from the installed extensions concatenated in the order they are loaded. Therefore including one of these files would be the same as including potentially hundred PHP-files and that saves some milliseconds for the system.

But it also means that a) you can never make any local changes to these files since they can at anytime be removed and recreated from the “originals” and b) if you make changes to the original “ext_tables.php”/”ext_localconf.php” files you will have to clear these files away!