To download the latest alpha or beta version:

```bash
$ cv dl --dev flexmailer
```

To download the latest, bleeding-edge code:

```bash
$ cv dl org.civicrm.flexmailer@https://github.com/civicrm/org.civicrm.flexmailer/archive/master.zip
```

To download the latest, bleeding-edge code from git:

```bash
$ cd $(cv path -x .)
$ git clone https://github.com/civicrm/org.civicrm.flexmailer.git
$ cv en flexmailer
```