Their specifications list the breathability level as: 10,000g/m2/24 hours. They don't list the test method which would make it very easy to accurately compare it to the breathability of other alternatives.
Based on the technology they used (laminated stretch polyurethane) it is most similar to the technology used in the Toray Dermizax three layer material. The Toray material tests 8,000g/m2/24 using the JIS L1099 B-1 test and in all probability this is the test that yielded the GoLite Trinity 10,000g/m2/24 hours result.
By contrast to Trinity's JIS L1099 B-1 rating of 10,000g/m2/24 other breathability results using the same tests are: eVENT, laminated to nylon, yields 27,826g/m2/24 hours; Gore-Tex XCR yields 21,194g/m2/24 hours; and Marmot PreCip yields the same at 10,000g/m2/24 hours.