Repository: matplotlib/matplotlib
File: lib/matplotlib/legend.py (Python)

Code before:
    Whether round edges should be enabled around the `.FancyBboxPatch` which
    makes up the legend's background.

shadow : None, bool or dict, default: :rc:`legend.shadow`
    Whether to draw a shadow behind the legend.
    The shadow can be configured using `.Patch` keywords.
    Customization via :rc:`legend.shadow` is currently not supported.

framealpha : float, default: :rc:`legend.framealpha`
    The alpha transparency of the legend's background.
    If *shadow* is activated and *framealpha* is ``None``, the default value is
    ignored.

facecolor : "inherit" or color, default: :rc:`legend.facecolor`
    The legend's background color.
    If ``"inherit"``, use :rc:`axes.facecolor`.

edgecolor : "inherit" or color, default: :rc:`legend.edgecolor`
    The legend's background patch edge color.
    If ``"inherit"``, use :rc:`axes.edgecolor`.

linewidth : float or None, default: :rc:`legend.linewidth`
    The legend's background patch edge linewidth.
    If ``None``, use :rc:`axes.linewidth`.

    .. versionadded:: 3.10

mode : {"expand", None}
    If *mode* is set to ``"expand"`` the legend will be horizontally
    expanded to fill the Axes area (or *bbox_to_anchor* if defines
    the legend's size).

bbox_transform : None or `~matplotlib.transforms.Transform`
    The transform for the bounding box (*bbox_to_anchor*). For a value
    of ``None`` (default) the Axes'
    :data:`!matplotlib.axes.Axes.transAxes` transform will be used.

title : str or None
    The legend's title. Default is no title (``None``).

title_fontproperties : None or `~matplotlib.font_manager.FontProperties` or dict
    The font properties of the legend's title. If None (default), the
    *title_fontsize* argument will be used if present; if *title_fontsize* is
    also None, the current :rc:`legend.title_fontsize` will be used.

title_fontsize : int or {'xx-small', 'x-small', 'small', 'medium', 'large', \
'x-large', 'xx-large'}, default: :rc:`legend.title_fontsize`
    The font size of the legend's title.
    Note: This cannot be combined with *title_fontproperties*. If you want
    to set the fontsize alongside other font properties, use the *size*
    parameter in *title_fontproperties*.

Review comment (suggestion):
```suggestion
    .. versionadded:: 3.11
```
v3.10 is already released.

Code after:
    Whether round edges should be enabled around the `.FancyBboxPatch` which
    makes up the legend's background.

shadow : None, bool or dict, default: :rc:`legend.shadow`
    Whether to draw a shadow behind the legend.
    The shadow can be configured using `.Patch` keywords.
    Customization via :rc:`legend.shadow` is currently not supported.

framealpha : float, default: :rc:`legend.framealpha`
    The alpha transparency of the legend's background.
    If *shadow* is activated and *framealpha* is ``None``, the default value is
    ignored.

facecolor : "inherit" or color, default: :rc:`legend.facecolor`
    The legend's background color.
    If ``"inherit"``, use :rc:`axes.facecolor`.

edgecolor : "inherit" or color, default: :rc:`legend.edgecolor`
    The legend's background patch edge color.
    If ``"inherit"``, use :rc:`axes.edgecolor`.

linewidth : float or None, default: :rc:`legend.linewidth`
    The legend's background patch edge linewidth.
    If ``None``, use :rc:`patch.linewidth`.

    .. versionadded:: 3.11

mode : {"expand", None}
    If *mode* is set to ``"expand"`` the legend will be horizontally
    expanded to fill the Axes area (or *bbox_to_anchor* if defines
    the legend's size).

bbox_transform : None or `~matplotlib.transforms.Transform`
    The transform for the bounding box (*bbox_to_anchor*). For a value
    of ``None`` (default) the Axes'
    :data:`!matplotlib.axes.Axes.transAxes` transform will be used.

title : str or None
    The legend's title. Default is no title (``None``).

title_fontproperties : None or `~matplotlib.font_manager.FontProperties` or dict
    The font properties of the legend's title. If None (default), the
    *title_fontsize* argument will be used if present; if *title_fontsize* is
    also None, the current :rc:`legend.title_fontsize` will be used.

title_fontsize : int or {'xx-small', 'x-small', 'small', 'medium', 'large', \
'x-large', 'xx-large'}, default: :rc:`legend.title_fontsize`
    The font size of the legend's title.
    Note: This cannot be combined with *title_fontproperties*. If you want
    to set the fontsize alongside other font properties, use the *size*
    parameter in *title_fontproperties*.