This is actually nothing at all to do with formatting; instead it’s what’s known as Z-encoding: see https://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/SymbolNames for details.

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EmbedTree_zdfLiftEntryzuzdclift_closure

I've seen something like this before -- I think the 'zd' and 'zu' in there are supposed to be formatting tokens, %zd and %zu, for architecture-aware data sizing. I ran into this while building the Haskell GTK bindings on Windows, and IIRC it was caused by GHC 7.8 bundling an older GCC.