packages are like the organs of a body.
this stucture has no function...
if you are not familar with the cmake written style, read the book “cmake实践”. But you dont need to know everything, since there will be a template generated by ros.
(obselete version of package.xml)
launch the excuatable files
可执行，脚本，通信，执行。
[ROS] Chinese MOOC || Chapter-2.2 Package组成
原文：https://www.cnblogs.com/ecoflex/p/10801520.html