ZShot is a browser automation program, similar to Puppeteer and Playwright, though focused primarily on generating screenshots, videos and archives.
If you have seen the ZShot User Agent in your webserver logs, that means that someone on the internet using the ZShot software has visited your site. A ZShot User Agent when not emulating another browser will typically look something like Mozilla/5.0 (compatible; zshot/1.0.0; +https://zshot-app.com/useragent.html) CEF/144.0.13+g9f739aa+chromium-144.0.7559.133.
If you would like to prevent a ZShot user from accessing your website, you can use a robots.txt instruction to indicate you would not like a ZShot user to access your content. An example block instruction would appear like so:
User-Agent: zshot
Disallow: /
Note that the creator of ZShot, Scale Assembly, is not able to provide support or information on the identity of users who have accessed your site. If you are trying to identify the origin of a ZShot user who has accessed your site, you should use network information from your logs along with information from publicly available registries like ARIN to identify usage.