As described in summary if I'm setting SPLASH = "plymouth" in os conf file and IMAGE_FEATURES:append = " splash" in initramfs image bb recipe, it does not append plymouth package to PACKAGE_INSTALL and there is no plymouth in /usr/share/ path.
Plymouth is in meta-oe: http://cgit.openembedded.org/meta-openembedded/tree/meta-oe/recipes-core/plymouth/plymouth_22.02.122.bb?h=master and that community does not use the Yocto (oe-core, bitbake, ....) bugzilla so please post an email / patch to openembedded-devel@lists.openembedded.org CCing Mingli who may be able to comment. Thanks. ../Randy