The main show piece of this module it the new MAX31329, from Analog Device, RTC with accuracy of 5 PMM, integrated crystal,  trickle charger, power management for backup of clock time which will run on a super capacitor, for a few days before charging is required.
 
The module it self features a power indicator LED, pin out pads, and 2 x 1mm JST SH connector for I2C , power and ground, so that it can be daisy chained with other devices, it also has 2 x 4.7k pullup resistors.
 
The MAX31329 has a long list of features:
• Increases Battery Life
• 240nA Timekeeping Current
• Trickle Charger for External Supercapacitor or Rechargeable Battery
• Provides Flexible Configurability
• A Schmitt Trigger Input for Event Detection
• Programmable Square-Wave Output for Clock Monitoring
• Two Interrupt Pins for Multiple Wakeup Configurations
• Clock Input Pin for External Clock Synchronization
• Saves Board Space
• Integrated Crystal and Load Capacitors Tuned to ±5ppm Typical Clock Accuracy
• 5mm x 5mm, 10-Pin LGA Package
• Value-Added Features for Ease-of-Use
• +1.6V to +5.5V Operating Voltage Range
• Two Time-of-Day Alarms
• Countdown Timer with Repeat and Pause Functions
• 64-Byte RAM for User Data Storage
• Integrated Protection
• Power-on Reset for Default Configuration
• Automatic Switchover to Backup Battery or Supercapacitor on Power-Fail
• Lockup-Free Operation with Bus Timeout
 
There is an Arduino Library that can be used to access most of the features of this RTC:  https://github.com/jeggleston1981/MAX31329