Yup that's malware. Escaped unicode? I'm more used to seeing straight up byte arrays get loaded into memory - this is probably obfuscated more? I've noticed similar escaped sequences in other files.
util > Internal.java
View attachment 4720892
Edit: question for minecraft players - does the minecraft server give you the mods you need on connect? Or does each player have to install the mod pack? Just wondering if there are players out there also popped. Who is the guy that sent these files to Claire?
Edit2: Oh someone said some mods look dodge like this normally.