In the 5.x installation procedure it says ...
As of eZ Publish 5.2, if you plan to use eZ Publish legacy only, as standalone (as in pointing apache to ezpublish_legacy folder or extracting only ezpublish_legacy), then Zetacomponents must be installed if you don't already have it via PEAR.
If we install the site via composer we will get zetacomponents/archive 1.5
If we install the zetacomponents via PEAR we will get components.ez.no/Archive-1.4.1
If the installation of zetacomponents via PEAR is not supported anymore (since it was intended for legacy), the documentation must be clear about it.
Otherwise, if it should be supported, the PEAR repository ezc/eZComponents should be updated.