There was no 1Password to LastPass importer at the time I wrote that (believe me, I looked because I have better things to do than write apps to benefit a commercial entity like agilebits otherwise), and of course the code is published on GitHub and released under the MIT license. It's very short and simple and rather easy to review. It's also a .NET executable, which is ridiculously easy to reverse-compile back to C# (not just assembly) so you can even check that I'm distributing an exe that does the same thing as the code I published.

EDIT

I just revisited that link I shared, and I have to say, it takes some real chutzpah to turn around and accusing me of advising insecure practice when the link I shared literally talks about just that:

Due to the nature of this application, 𝘄𝗲 𝘀𝘁𝗿𝗼𝗻𝗴𝗹𝘆 𝘂𝗿𝗴𝗲 𝗲𝘃𝗲𝗿𝘆𝗼𝗻𝗲 𝘁𝗼 𝗱𝗼𝘄𝗻𝗹𝗼𝗮𝗱 𝘁𝗵𝗲 𝘀𝗼𝘂𝗿𝗰𝗲 𝗰𝗼𝗱𝗲, review it quickly, and compile it yourself to use this tool. However, we do recognize that this may be beyond the means of all security-minded folk out there looking to make the switch, so we are providing signed binaries available for download. If you do opt to use the binary download, make sure to validate the authenticode signature like so: ...