Researchers should understand if the terms of third party’s software license are acceptable and do not diverge from the goal they want to achieve using such software. This could be the case if researchers do not want to share their own source code, or if licensing the new software to a company or a startup can be foreseen.
For software available on the web the license (i.e. the rights and duties related to the software) is generally accessible in the license file or headers attached with the code or the executable.
Analyzing the terms of the license (e.g. open source, accademic or commercial) allows clarifying what you will have the right, or the obligation to do with the software.