Weird white space in admin area

Well that didn’t take long to figure out..
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I’ve dealt with this before, but could never figure it out. Obfuscated code. Impulsively I deleted the directory, but they’ll be back.
If you see these weird random PHP files, your site needs to be scrubbed and relaunched from backups. Preferably XML data files with no code. Reload the entire site from sources.