blockland addons containing files such as
.cs
.txt
.wav
.dts
.png
.ogg
files are essentially inescapable of inflicting any damage to your computer as they are just data parsed through blockland
the only time you need to worry about files are when they are things like executable that you allow to execute by opening them, so as long as you don't open any untrustworthy executable the likelihood of you getting viruses is almost none save for the very slim occasions where trusted products have security holes which are usually patched out very fast after discovery