該版本在 Firefox 3.6.9pre 版本上通過全面測試，在 Firefox 4.0 b4 上有六項測試失敗，主要問題請看：known issues in the Firefox beta release.
Firebug 1.6 b1 修復了 Firebug 1.6 a20 的 7 個bug。
Firebug 1.6 整個版本主要的改進包括：
* Option to use en-US locale
* First run page comes up on install or update.
* Support for Firefox 4.0
* getfirebug.com TestBot results page
* Command line available on all panels
* Net panel reports BFCache hits
* Command line completion rewrite
* implemented console.table
* Disabling break on next error and debugger; keywords.
* forward and back arrows in the toolbar
* MozAfterPaint events now show up on the net panel time line
* Scrolling Panels Tab Bar.