those files are part of 7.6.0 install.

your title says you are attempting to install 7.6.1.

you should be able to upgrade directly from 7.5.5 to 7.6.1 WITHOUT needing to incrementally update from one version to the next higher one, and then to the next one...etc

remove your current /install directory, and replace it with the one found inside the 7.6.1 zip archive, and begin your upgrade again.

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