Source: Noto Sans Symbols2

U+0003 End of Text *

U+0003 was added in Unicode version 1.1 in 1993. It belongs to the block U+0000 to U+007F Basic Latin in the U+0000 to U+FFFF Basic Multilingual Plane.

This character is a Control and is commonly used, that is, in no specific script. The character is also known as END OF TEXT.

The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it acts as Boundary Neutral. When changing direction it is not mirrored. U+0003 prohibits a line break before it.

The Wikipedia has the following information about this codepoint:

The End-of-Text character (ETX) is a control character used to inform the receiving computer that the end of a record has been reached. This may or may not be an indication that all of the data in a record have been received. It is often used in conjunction with Start of Text (STX) and Data Link Escape (DLE), e.g., to distinguish data frames in the data link layer. All this use is pretty much obsolete.
In both ASCII and EBCDIC, ETX is code point 0x03, often displayed as ^C, and a (ASCII) terminal can send it by typing Ctrl+C.
Control-C is often used to interrupt a program or process, a standard that started with Dec operating systems. In TOPS-20, it was used to gain the system's attention before logging in. mIRC uses ETX as the escape character to start a command to set the color.

Representations

System	Representation
Nº	3
UTF-8	03
UTF-16	00 03
UTF-32	00 00 00 03
URL-Quoted	%03
HTML hex reference
Wrong windows-1252 Mojibake	âƒ
Caret Notation	^C
control	END OF TEXT
abbreviation	ETX
alias	END OF TEXT
Adobe Glyph List	controlETX
digraph	EX

Elsewhere

Complete Record

Property	Value
Age (age)	1.1 (1993)
Unicode Name (na)	—
Unicode 1 Name (na1)	END OF TEXT
Block (blk)	Basic Latin
General Category (gc)	Control
Script (sc)	Common
Bidirectional Category (bc)	Boundary Neutral
Combining Class (ccc)	Not Reordered
Decomposition Type (dt)	none
Decomposition Mapping (dm)	End of Text*
Lowercase (Lower)	✘
Simple Lowercase Mapping (slc)	End of Text*
Lowercase Mapping (lc)	End of Text*
Uppercase (Upper)	✘
Simple Uppercase Mapping (suc)	End of Text*
Uppercase Mapping (uc)	End of Text*
Simple Titlecase Mapping (stc)	End of Text*
Titlecase Mapping (tc)	End of Text*
Case Folding (cf)	End of Text*
ASCII Hex Digit (AHex)	✘
Alphabetic (Alpha)	✘
Bidi Control (Bidi_C)	✘
Bidi Mirrored (Bidi_M)	✘
Composition Exclusion (CE)	✘
Case Ignorable (CI)	✘
Changes When Casefolded (CWCF)	✘
Changes When Casemapped (CWCM)	✘
Changes When NFKC Casefolded (CWKCF)	✘
Changes When Lowercased (CWL)	✘
Changes When Titlecased (CWT)	✘
Changes When Uppercased (CWU)	✘
Cased (Cased)	✘
Full Composition Exclusion (Comp_Ex)	✘
Default Ignorable Code Point (DI)	✘
Dash (Dash)	✘
Deprecated (Dep)	✘
Diacritic (Dia)	✘
Emoji Modifier Base (EBase)	✘
Emoji Component (EComp)	✘
Emoji Modifier (EMod)	✘
Emoji Presentation (EPres)	✘
Emoji (Emoji)	✘
Extender (Ext)	✘
Extended Pictographic (ExtPict)	✘
FC NFKC Closure (FC_NFKC)	End of Text*
Grapheme Cluster Break (GCB)	Control
Grapheme Base (Gr_Base)	✘
Grapheme Extend (Gr_Ext)	✘
Grapheme Link (Gr_Link)	✘
Hex Digit (Hex)	✘
Hyphen (Hyphen)	✘
ID Continue (IDC)	✘
ID Start (IDS)	✘
IDS Binary Operator (IDSB)	✘
IDS Trinary Operator and (IDST)	✘
IDSU (IDSU)	0
ID_Compat_Math_Continue (ID_Compat_Math_Continue)	0
ID_Compat_Math_Start (ID_Compat_Math_Start)	0
Ideographic (Ideo)	✘
InCB (InCB)	None
Indic Mantra Category (InMC)	—
Indic Positional Category (InPC)	NA
Indic Syllabic Category (InSC)	Other
Jamo Short Name (JSN)	—
Join Control (Join_C)	✘
Logical Order Exception (LOE)	✘
Math (Math)	✘
Noncharacter Code Point (NChar)	✘
NFC Quick Check (NFC_QC)	Yes
NFD Quick Check (NFD_QC)	Yes
NFKC Casefold (NFKC_CF)	End of Text*
NFKC Quick Check (NFKC_QC)	Yes
NFKC_SCF (NFKC_SCF)	End of Text*
NFKD Quick Check (NFKD_QC)	Yes
Other Alphabetic (OAlpha)	✘
Other Default Ignorable Code Point (ODI)	✘
Other Grapheme Extend (OGr_Ext)	✘
Other ID Continue (OIDC)	✘
Other ID Start (OIDS)	✘
Other Lowercase (OLower)	✘
Other Math (OMath)	✘
Other Uppercase (OUpper)	✘
Prepended Concatenation Mark (PCM)	✘
Pattern Syntax (Pat_Syn)	✘
Pattern White Space (Pat_WS)	✘
Quotation Mark (QMark)	✘
Regional Indicator (RI)	✘
Radical (Radical)	✘
Sentence Break (SB)	Other
Soft Dotted (SD)	✘
Sentence Terminal (STerm)	✘
Terminal Punctuation (Term)	✘
Unified Ideograph (UIdeo)	✘
Variation Selector (VS)	✘
Word Break (WB)	Other
White Space (WSpace)	✘
XID Continue (XIDC)	✘
XID Start (XIDS)	✘
Expands On NFC (XO_NFC)	✘
Expands On NFD (XO_NFD)	✘
Expands On NFKC (XO_NFKC)	✘
Expands On NFKD (XO_NFKD)	✘
Bidi Paired Bracket (bpb)	End of Text*
Bidi Paired Bracket Type (bpt)	None
East Asian Width (ea)	neutral
Hangul Syllable Type (hst)	Not Applicable
ISO 10646 Comment (isc)	—
Joining Group (jg)	No_Joining_Group
Joining Type (jt)	Non Joining
Line Break (lb)	Combining Mark
Numeric Type (nt)	none
Numeric Value (nv)	not a number
Simple Case Folding (scf)	End of Text*
Script Extension (scx)
Vertical Orientation (vo)	R