It has been discussed one day on ezjscore forum:
http://projects.ez.no/ezjscore/forum/general/disable_packer_in_design_ini_frontendjavascriptlist

I have in fact a lot of javascripts in my design.ini, for example:

[JavaScriptSettings]
FrontendJavaScriptList[]=djgfx::js
FrontendJavaScriptList[]=http://domain.com/remote.js
FrontendJavaScriptList[]=external-lib.js
FrontendJavaScriptList[]=custom-javascript.js

And the equivalent in some tpl

{ezscript_require( array( 'djgfx.js', 'http://domain.com/remote.js', 'external-lib.js', 'custom-javascript.js' ) )}

I run jslint automatically on my .js (djgfx::js and custom-javascript.js) so these both files can be packed at level 3, the maximum

However, I also use external .js (http://domain.com/remote.js and external-lib.js). Those should only be minified at level 2, as I can't modify them to respect jslint

As a result, due to the 2 latter, I have to use Packer=2 for all, which is not optimum

=> It would be very nice to use the default Packer settings, but be also possible to define the Packer settings, per file also to have a Packer different than the default Packer

I could have in my case, in design.ini, something like this:

[JavaScriptSettings]
FrontendJavaScriptList[]=3||djgfx::js
FrontendJavaScriptList[]=http://domain.com/remote.js
FrontendJavaScriptList[]=external-lib.js
FrontendJavaScriptList[]=3||custom-javascript.js

and in the .tpl:

{ezscript_require( array( '3||djgfx.js', 'http://domain.com/remote.js', 'external-lib.js', '3||custom-javascript.js' ) )}

Here, the 3|| could indicate to ezjscore "please use Packer=3 for this file, and not the default Packer".
And if no || in it, then use the default Packer settings (which is 2)

All the packer job seems to be done in extension/ezjscore/classes/ezjscpacker.php, via the function packFiles. I guess a patch would concern only this function