Deleting INI, SIL, XML files from C:\

Seems to me these files were once created by X1.
As most are '0-bytes' - I wonder whether they (still) serve any purpose, i.e. can I delete them?
That aside, why aren't they stored in the program folder?

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Attachment.config.ini
Calendar.config.ini
Contact.config.ini
counts.ini
Email.config.ini
federation.ini
Files.config.ini
IM.config.ini
Journal.config.ini
Notes.config.ini
server.ini
Tasks.config.ini
Web.config.ini
X1Config.ini
crash.log
servCrash.log
translations.sil
ScrubRetValFile.txt
favtree.xml
searchestree.xml
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