To avoid confusion, the Svirfneblin subrace does not have the same ability-modifiers and statistics as listed on http://www.escapefromunderdark.com/applications.html

The website gives them -2 STR, while the subrace self gets -2 CON. Furthermore, the website lists them at Spell Resistance 11 + level, whereas they get 10 + level.

Nothing too major, but worth noting.

Subrace CR is rounded to an even number for various technical reasons.

And the adjustments are there because they're compensating for the Rock Gnome adjustments (+2 con, -2 str). So all is well.