The interim FAR (Federal Acquisition Regulation) rule on sick leave from December 2016 has now become final and the permanent rule didn't change from the interim rule.
Under this sick leave rule, contractors must allow employees, both full and part-time, one hour of sick leave for every hour worked. Alternatively, they can accrue 56 hours at the beginning of the year and allow employees to take it throughout the year.
Most contractors were not likely impacted by the interim rule and won't be impacted by the final rule either as their sick leave policies already exceed the minimum required by the rule. Also, many states have adopted or are adopting minimal sick leave benefits for all employers so the Federal rule covering Government contractors becomes a moot point.
This rule was initially based on an Executive Order from the previous administration and there was speculation for awhile that the current President would retract it. However, he let it stand, probably because no one was clamoring for its repeal plus the fact that many states had already adopted similar rules.
Details of the Sick Leave rule can be found in the publication of the interim rule.
Federal Register details of the final rule can be found here.