constant FILE_EXISTS_REPLACE in Zircon Profile 8

AssetDumper::dump in core/lib/Drupal/Core/Asset/AssetDumper.php

The file name for the CSS or JS cache file is generated from the hash of the aggregated contents of the files in $data. This forces proxies and browsers to download new CSS when the CSS changes.

CopyTest::testExistingReplace in core/modules/file/src/Tests/CopyTest.php

Test replacement when copying over a file that already exists.

DirectoryTest::testFileDestination in core/modules/system/src/Tests/File/DirectoryTest.php

This will test the filepath for a destination based on passed flags and whether or not the file exists.

EntityFile::getOverwriteMode in core/modules/file/src/Plugin/migrate/destination/EntityFile.php

Determines how to handle file conflicts.

EntityFileTest::testGetOverwriteMode in core/modules/file/src/Tests/Migrate/EntityFileTest.php

Tests various invocations of the getOverwriteMode() method.

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