What does it look like and what can be the consequences?
Your developers' understanding of the source code is the key factor to actively managing the process of generating software. Given that each individual developer has her/his special field of interest and proficiency, a complete specialization and isolation bears an enormous risk.
The software map shows those areas which were only ever altered by one developer. The high purple "code objects" indicate a high level of complexity. There are two complex sections of source code, just one person of your organization can profoundly work with. Sections, just one developer can easily navigate in, understand dependencies and fix errors in a reasonable time frame.
In the context of efficient software development and effective software development management, this is truely a situation to be avoided. Why? Just imagine this developer's knowledge is removed by circumstances beyond the organization's control, e.g. leaving the organization, sickness or other uncontrollable events.