Post Custom Templates will help you in changing your theme's default demplate for single posts. You can also create custom templates - drag & drop, no codding.
Observations, not findings. Every construct below appears in ordinary, legitimate plugins — they are listed so you can judge for yourself. Only ClamAV decides this package's verdict.
unserialize
Unsafe when given untrusted input
Deserialization6
curl_exec
Makes an outbound HTTP request
Remote request2
base64_decode
Decodes base64 — routine, but also how packed code hides
Obfuscation1
eval
Executes a string as code
Code execution1
Referenced hosts
20 distinct
Domains appearing in the package source. Most are documentation links or CDNs; their presence is not evidence the package contacts them.