A simple open source tool with LGPL 2.1 license to validate whether a single or a folder of LAS or LAZ files conform to the LAS specification of the ASPRS. If something goes wrong during your LiDAR processing with LAStools it is good to run a lasvalidate check before asking a question in the LAStools user forum as the validation report will find corrupt or odd files. This is not an official validator but the LiDAR community has widely accepted it. You can comment on the LASvalidator via the LAS room or contribute via Github.
lasvalidate -i lidar.laz -o report.xml
For more details see the README file.