1. A computer program product comprising a computer readable storage medium having stored thereon: first program instructions programmed to receive a first functional component of a set of source code; second program instructions programmed to receive a set of knowledgeable person(s) information including identifying information for at least one person and respectively associated availability information for each identified person, where each person identified in the set of knowledgeable person(s) information has knowledge of the first functional component; third program instructions programmed to calculate, based, at least in part, on the identified person(s) and their respectively associated availability information, a confidence value for the first functional component relating to the availability of person(s) with knowledge of the first functional component; and fourth program instructions programmed to determine, for each identified person, a knowledge score corresponding to the respective person's knowledge of the first functional component; wherein: the calculating of the confidence value for the first functional component is further based, at least in part, on the respective knowledge score for each identified person; each person identified in the set of knowledgeable person(s) is at least one of the following: a contributor to the first functional component; a frequent user of the first functional component; a contributor to a second functional component of the set of source code, where the second functional component is a parent component and/or a child component of the first functional component; a frequent user of the second functional component; a contributor to a third functional component of the set of source code, where the third functional component includes similar source code to the source code included in the first functional component but is not a parent or child component of the first functional component or the second functional component; and/or a frequent user of the third functional component; the determined knowledge score for an identified person is higher when the respective person is a contributor and/or a user of the first functional component than when the respective person is a contributor and/or a user of the second functional component; and the determined knowledge score for an identified person is higher when the respective person is a contributor and/or a user of the second functional component than when the respective person is a contributor and/or a user of the third functional component.