On 7 August 2014 Google published a second L Preview build, LPV81C, for the
same two devices: the Nexus 5 and the Nexus 7 (2013) Wi-Fi. It came with the
Google Fit Developer Preview, not with an Android announcement. Google’s Fit
page called it “a special version of the Android L Developer Preview system
image with Google Fit support” and told developers not to use the images on
the Android preview site, which kept offering LPV79 until October.
Apps built on it still targeted 'android-L' with no API level, and Fit apps
could not be published on Google Play until Google Fit launched. Droid Life
reported the build the same day and found nothing else announced in it.