MAMP Pro license record
The MAMP Pro 1.0/2.0/2.0 upgrade/3.0 serial numbers are stored in the following files:
"/Library/Application Support/appsolute/MAMP PRO/Registration 1.0" or
"/Library/Application Support/appsolute/MAMP PRO/Registration 2.0" or
"/Library/Application Support/appsolute/MAMP PRO/Registration upgrade 1.0 to 2.0" or
"/Library/Application Support/appsolute/MAMP PRO/Registration 3.0"

Example:  

&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt;
&lt;plist version="1.0"&gt;
&lt;dict&gt;
&lt;key&gt;sn&lt;/key&gt;
&lt;string&gt;AABB1122CCDD33AA1&lt;/string&gt;
&lt;/dict&gt;
&lt;/plist&gt;


Your serial number is then string : AABB-1122-CCDD-33AA1

In MAMP Pro 4 and 5 the serial number is longer and is prefixed with an "MP" (which won't occur in the sn-string).

Files:

"/Library/Application Support/appsolute/MAMP PRO/Registration 4.0" or
"/Library/Application Support/appsolute/MAMP PRO/Registration upgrade 4.x to 5.x" or
"/Library/Application Support/appsolute/MAMP PRO/Registration 5.x"

Example:  

&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt;
&lt;plist version="1.0"&gt;
&lt;dict&gt;
&lt;key&gt;sn&lt;/key&gt;
&lt;string&gt;11112A2AB333C4444DD55EE66F7F7ABCDEA&lt;/string&gt;
&lt;/dict&gt;
&lt;/plist&gt;


The serial number would be: MP-1111-2A2A-B333-C4444-DD55-EE66-F7F7-ABCDE-A

(don't try it – it's probably no valid number because I modified my own serial number massively)