Library quality check before capturing

[polymerase1986]

Dear all

To check the quality of the genomic DNA library, our collaborators performed a Titration run (1x50) on HiSeq and provided us 50 fasta sequences plus 100'000 fast-q sequences for each library.
Does this mean, that they loaded the created labrary (prior the exome capturing step) on a flow cell? or how does this work? Does anyone have experience with that? What does titration run mean?

Is the quality of the library at this stage - prior to the exome capturing - comparable with the quality of the library after the capturing step?

Thanks a lot for your answers!!