In what cases are BLOB and TEXT stored in-line on InnoDB?
Keep in mind that there are 4 &quot;row formats&quot;.  A main difference between then has to do with how wide columns are handled.
The reference points to an Answer written early in 2010, a few months before DYNAMIC and COMPRESSED were introduced in the &quot;InnoDB plugin&quot;.
So, I claim that that other Q&amp;A is out of date!  That is the 754 Upvotes are no longer valid.
Here are some 'current' manual references:
(emphasis mine)
From https://dev.mysql.com/doc/refman/5.6/en/innodb-row-format-overview.html :

Columns such as BLOB and VARCHAR that are too long to fit on a B-tree page are stored on separately allocated disk pages called overflow pages.

From https://dev.mysql.com/doc/refman/5.6/en/innodb-row-format-dynamic.html :

When a table is created with ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED, InnoDB can store long variable-length column values (for VARCHAR, VARBINARY, and BLOB and TEXT types) fully off-page, with the clustered index record containing only a 20-byte pointer to the overflow page.
[DYNAMIC and COMPRESSED] When the row is too long, InnoDB chooses the longest columns for off-page storage until the clustered index record fits on the B-tree page. TEXT and BLOB columns that are less than or equal to 40 bytes are always stored in-line.
The DYNAMIC format is based on the idea that if a portion of a long data value is stored off-page, it is usually most efficient to store all of the value off-page. With DYNAMIC format, shorter columns are likely to remain in the B-tree node, minimizing the number of overflow pages needed for any given row.
The COMPRESSED row format uses similar internal details for off-page storage as the DYNAMIC row format

From https://dev.mysql.com/doc/refman/5.6/en/innodb-physical-record.html (even a big CHAR may be treated like TEXT):

InnoDB [all formats?] encodes fixed-length fields greater than or equal to 768 bytes in length as variable-length fields, which can be stored off-page. For example, a CHAR(255) column can exceed 768 bytes if the maximum byte length of the character set is greater than 3, as it is with utf8mb4.
ROW_FORMAT=DYNAMIC and ROW_FORMAT=COMPRESSED handle CHAR storage in the same way as ROW_FORMAT=COMPACT.

(The links are for 5.6, but I think the text applies at least to newer versions.)
I see nothing specific that says that VARCHAR(...) and *TEXT are handled differently.