Instr - instructors manual (if not present it is automatically participants manual)
Internal - internal document (usually locked against printing and copy&paste operations)
Scan - scanned document (no able to search - only pictures)
A4 - paper format A4
Ltr - paper format Letter
Show - slide show presentation
二、
<course code>_<language>_Col<collection>_FV_{ Part | Inst }_{ A4 | Ltr }.pdf
for example: HR550_EN_Col52_FV_Part_A4.pdf
Where:
Part - participant manual
Inst - instructor manual
A4 - paper format A4
Ltr - paper format letter
look on course:
EP200_-_2004-Q2_Instr_-_Ltr_-_SAP_Enterprise_Portal_System_Administration.pdf
you can find the course in the "Download All SAP Materials - A TO Z ! Free SAP Tutorials" thread - you have instructor course in Ltr format.
I think that in europe A4 format is normal and in USA letter format is common. SAP is not so common in US like in Europe - maybe that is reason why most of the courses are in A4 format.