The place keyword replaces the place= attribute of <note>, <add>, and <addSpan>. It indicates the vertical and horizontal position of elements which can occur anywhere on the page, and whose vertical position is not determined by their location within the encoded stream of text. (This distinguishes it from the align keyword, which is used to indicate the horizontal position of elements which can only “slide” horizontally, and whose vertical position is indicated by where they are encoded.)
Some of the possible values for the place keyword apply only to <add> and <addSpan>, some apply only to <note>, and others are common to all three elements.
1. Values which apply to <add>, <addSpan>, and <note>
These values indicate that the element appears in the left or right margin of the page. (See outside and inside, below.)
2. Values which apply only to <add> and <addSpan>
inline (for additions which are inline; for instance, overwriting or additions to the end of a line)
supra (for additions above the line)
infra (for additions below the line)
top (for additions which appear at the top of the page)
bottom (for additions which appear at the bottom of the page)
The “top” and “bottom” values are useful if the addition is marked with some sort of anchor within the text, rather than being completely separate from the text flow.
3. Values which apply only to <note> and in some cases <stage>
outside, inside (these indicate that the note appears in the outside or inside margin; can be useful for setting defaults, since it makes it unnecessary to use “left” and “right” in cases where the note is always on the inside or outside margin)
opposite (for notes which fall on the page opposite the one where they are anchored)
overleaf (for notes which are anchored on a recto page but fall on the verso of that page)
inset-left, inset-right, inset-outside, inset-inside (for notes which actually intrude into the text block rather than being out in the margin; these values interact in the same way that left/right/inside/outside do). Note that these “inset-foo” values should only be used in cases where a space in the main text block has been carved out for the insertion of a marginal note, stage direction, or other piece of text which is not part of the main reading flow of the text. They should not be used for cases where text blocks are placed horizontally across the page (e.g. in closers and openers, where there may be several little chunks of text arranged next to one another).
foot, end (these indicate whether a note is an endnote or a footnote)
headspace, footspace (these indicate a specific part of the space at the top or bottom of the page, but it would be better just to use “top” and “bottom” for the time being)
mixed (this indicates that the element in question is in various places too numerous to mention)