Same, going to direct sourceforge page gives same warning.
It’s also not the only time I’ve encountered this at sourceforge.
I’ve downloaded and installed Manjaro versions before and same warning had occurred.
And I thought it (the sourceforge security issue) had been fixed since 
It obviously wasn’t.
Oh, BTW, downloaded kde pre 1 (despite warning, as before), installed and works well (as before).
 - some links on sourceforge security issues
o wikipedia page.
On July 1, 2013, SourceForge began a beta test of a program they call DevShare, which offers projects a way to monetize their downloads by having an optional download that includes prompts for the user to download additional software that is not part of the project. Due to community reactions to the partnership program, it was revisited a few months later, but the program was ultimately opened up to all SourceForge projects on February 7, 2014. The program was cancelled by new owners BIZX in February 2016.
o Another link
It appears as if the new owners at SourceForge are serious about fixing the mistakes made by the site’s previous owners. FOSS Force has learned that as of today, the software repository used by many free and open source projects is scanning all hosted projects for malware. Projects that don’t make the grade will be noticeably flagged with a red warning badge located beside the project’s download button.
‘bold’ lettering - my emphasis.