EDIT: Meanwhile I tracked down the bug further. The problem is that when using "-debug=[true|false] concat", any exclude statements will be ignored. See post #3.

Sencha Cmd 3.0.0.250
ExtJs 4.1.1a
Win 7 x64
command: 'sencha compile'

Summary

Using 'sencha compile', ExtJs core classes are being added to the compiled output despite explicitly being excluded with 'exclude -tag core'. This worked correctly in 3.0.0.181

Test Case:
The output of the compiler script below will include several files from src/core which shouldn't be there because 'foundation' and 'core' are excluded via tags.

Code:
compile
-cl=extjs-4.1.1a/src,app/
union
-r
-c
myapp.Application
and
exclude
-tag
core
and
exclude
-tag
foundation
and
-debug=false
concat
-strip
-compress
build/all.min.js
and
metadata
-f
-o
build/all-dependencies.txt
Interestingly, it seems to work correctly if we drop the 'concat' and only use metadata. The resulting metadata file will **not** include files from 'src/core'.

Code:
compile
-cl=extjs-4.1.1a/src,classes
union
-r
-c
myapp.Application
and
exclude
-tag
core
and
exclude
-tag
foundation
and
metadata
-f
-o
build/all-dependencies.txt