Browserhax exploits various vulnerabilities in the system web-browsers, see the below repositories for details.
The following browser exploits can be used to boot the hblauncher payload:
A hosted version of these is available here: 
July 27, 2016
- The latest Old3DS/New3DS browser versions as of 11.0.0-33 are now supported.
- Sliderhax is now obsolete since it was replaced with another exploit(it's still accessible however).
- Added support for more non-<USA/EUR/JPN> browser versions.
- Every version of the USA/EUR/JPN Old3DS browsers are now properly supported(previously support for the older versions were broken).
- When requesting the payload-URL for the current system-version, and when downloading the actual *hax payload, the loader now only uses HTTPS.
- Fixed hangs in HTTPC_CloseContext when an error previously occurred prior to using HTTPC_ReceiveData.
- Major improvements with the Old3DS-browserhax loader. With these changes, Home Menu takeover has never failed pre-release, even with >=v10.4 NATIVE_FIRM.
- Fixed issue where new3ds menu takeover would fail when theme-shuffling is enabled.